Aua. 1894.] HA.NKIN ON TYPHOID OUTBREAKS. 281

irigiirot ^omntmtiqations.

OBSERVATIONS ON TYPHOID OUTBREAKS.

By E. H. Hankin, m.a., Fellow of St. John's College, Cambridge, Chemical Examiner

and Bacteriologist to the North- Western Provinces and Oudli and Central Provinces.

I.?Typhoid and "Dahi."

Some dahi that was captured while being smuggled into the Officers' Mess of the East Sur- rey Regiment, was recently sent me by Surgeon- Major Milward, A.M.S. In it I found the typhoid bacillus besides other microbes, and as my obser- vations show the possibility of a connection between this substance and typhoid outbreaks, I think an account of the natural history of dahi may be of interest.

In Agra, at all events, dahi is made not by milkmen or givallas, but by the hulwais or

confectioners. The process is as follows :? Late in the evening, when trade is slacken-

ing, all that is left over of the day's milk is put into a large iron-vessel known as a kurhao and thoroughly boiled. It is then taken off the fire and allowed to cool. The cooling is often quick- ened by ladling up the milk and pouring it

slowly back from a height. When tolerably cool the milk is transferred to large shallow vessels known as kundi or Jcunda. To each kundi a small quantity of yesterday's dahi is added ; perhaps about two chittacks of dahi are added to five seers of milk. This addition is com-

monly called the zamin (surety) or the jorun (fixer). Each kundi is then covered with a similar vessel and put into a cool place if the weather is hot, or a warm place if the weather is cold. The next morning the whole of the milk is found to be coagulated, that is to say, changed into dahi and ready for sale. The above facts obviously suggest that the process is due to the presence of a ferment, and therefore, as I was afterwards able to prove, caused by a microbe. The natives are aware that if the zamin be placed in boiling milk no dahi will be formed. They are not aware of the reason of this fact, which is that the heat destroys the microbe on which the fer- mentation depends. They are also aware that the best dahi is ouly made when good dahi is used to inoculate the milk, a zamin of bad dahi no doubt containing many foreign microbes. With some difficulty 1 succeeded in isolating the dahi microbe. Dahi when examined under the micro- scope is seen to contain (1) a large non-motile bacillus in large numbers; (2) a yeast plant or torula whose cells being mostly isolated and

superficially resembling fat globules are easily overlooked; (3) a slightly smaller bacillus present in small numbers; and occasionally (4) a diplo- coccus. Practically the same appearances were observed in dahi coming from three different

sources. On making surface cultures of dahi

(not that from the Mess) on agar-agar in such a way as to produce isolated colonies, only the toru- la was found to have developed after twenty-four hours. In fact, the inoculation appeared to have produced a pure culture of this torula, and na- turally I expected that it would turn out to be the dahi-formmg microbe. Nevertheless I found that it has absolutely no power of coagulating milk. Indeed, it seems to have no power or scarcely any power of growing in that liquid in the ab- sence of other microbes. Forty-eight hours, how- ever, after the inoculation of the agar-agar some

very minute colonies had developed in addition to the original torula colonies, and which were so small and transparent as only to be visible with difficulty. These colonies were of two kinds,? one?the less transparent?consisted of a small thin bacillus which also has no power of coagu- lating milk. The other consisted of a large bacillus forming long tangled chains extending over several fields of view. A trace of a colony of this microbe when inoculated into sterilized milk caused its transformation into dahi within twenty- four hours, and the latter when inoculated on to agar-agar produced a pure culture of the same bacillus. If milk is inoculated with this microbe and examined in drop cultures, the milk is seen to coagulate first in the neighbourhood of the bacilli; and these bacilli are seen to have the

power of rapid reproduction in milk to an extent that bears no comparison to their feeble powers of growth upon agar-agar. There is then no doubt that the above peculiar microbe, which may be called the bacillus dahii, is, at any rate in Agra, the cause of the transformation of milk into dahi. The bacillus dahii is nearly two micro-milli-

metres wide and of very varying length. In milk the separate joints are commonly eight or ten micro-millimetres long and chains of six or eight individuals can be observed. Its ends are parti- cularly blunt, almost square, thus giving it a resemblance to the microbe of anthrax. On agar- agar, as above-mentioned, it grows out into long tangled filaments. In dahi a faint granulation of the bacilli is sometimes visible. In this medium the bacilli are after some hours' devel-

opment seen to be surrounded by a clear space, distinct from the surrounding clot. Very pro- bably this is due to the microbe first secreting a rennet-ferment which clots the milk, and then a peptonizing ferment which slowly dissolves the clot, as is often the case with other microbes which have a similar, though, I believe, slighter power of acting on milk. The colonies on agar- agar are about as large in area as a pin's head. They have a somewhat mottled appearance and slightly irregular outline. Their colour is white, but they are very thin and translucent, and scarcely raised above the surrounding surface of the medium. The bacillus does not grow in

41

282 INDIAN MEDICAL GAZETTE. [Aua. 1894.

bouillon or on potato. Owing to the tempera- ture of my laboratory, I am not able to test its

growth in gelatine. . As above mentioned I obtained the typhoid

bacillus from the dahi found in the East Surrey Mess. I isolated it by means of carbolized bouil- lon, and identified it by the following charac- ters :?

. (1) Its peculiar and rapid method of locomo- tion which, according to some authors, is quite characteristic;

(2) Its tendency to form long chains when

grown in bouillon, as also its power of growing in carbolized bouillon;

(3) Its invisible growth on potato ; (4) The fact that when grown on agar-agar

tinted-blue with litmus, and containing two per cent, of lactose, the mixture undergoes no change of colour; and

(5) The fact that when grown in milk, the liquid is not coagulated. The above characters are amply sufficient

to identify the bacillus in question as that of typhoid. The question now arises, how did this typhoid

bacillus get into the dahi ? It is unlikely that it was due to an accidental

contamination by dust or other cause during the short time that the dahi was in the East

Surrey Mess; for though I am unable to make

any definite statement, I have formed the im-

pression that it was present in considerable

quantity. At any rate the typhoid baccillus and the above-mentioned torula appeared to be the only microbes present that grew rapidly on agar. Some of the East Surrey dahi (taken from beneath the surface) produced a culture in which only the above microbes could be seen on microscopic examination: and in cultures of the same dahi in carbolized bouillon only the same two microbes developed.

Since the typhoid bacillus is killed by boiling, an'd since the milk from which the dahi is made is boiled, there is no prima facie reason for sus- pecting the cows or the dairy. It is then likely that the microbe got in between the time that its nidus was poured out of the kurliao as milk and its being placed in the hhansamatis chattie as dahi. This period is passed as above-men- tioned in the shallow earthen vessel known as

the Jcundi. Well-to-do natives when making dahi prefer to use a new Jcundi, but I believe the hulwais only use a new Jcundi when the old one is broken, consequently the lcundi has to be washed occasionally or at least wiped with a

wet rag. The water used in this process is with

little doubt the fons et origo mali. If this sup-

position is correct, one might expect to find a well near where the dahi was made whose water was specially liable to be contaminated with the dejecta of natives. Natives appear to be natu-

rally insusceptible to typhoid. This is certainly

not due to their not swallowing the microbe. The typhoid bacillus seems to be a relatively harmless inhabitant of their intestines. Here it can probably increase and multiply and then pass into the dejecta without trouble to either host or parasite. Hoping to be able to find some evidence in

favour of the above conjectures, I attempted to find the address of the confectioner who had made the dahi from the mess khansamah. But I found that individual to be more concerned in

proving that he had not broken the rule about not bringing things from the bazaar into the Mess than in aiding the progress of science, and as regards the uses of dahi his mind was a per- fect vacuum. However, he stated that the milkman who had beeu discharged three days previously would be able to corroborate some of the details of his story. I accordingly went to the milkman, and after listening to the corro- borations, pointed out to him that I thought that there were no grounds for the supposition on the part of the officers that his milk was bad, but that I thought that some dahi that had been brought into the Mess some days before was the cause of the illness of the sahibs, and that to prove this idea I must know where the. confectioner lived who had made it. The man

immediately told me the address; and as he

obviously saw that it was to his advantage to,

speak the truth, I have little doubt that he was indulging in that unusual luxury on this occa- sion. On arriving at the confectioner's shop in the Sudder Bazaar, I found, as I had expected, that the nearest water-supply was a well with peculiarly dirty surroundings, such as, I believe, does not exist elsewhere in cantonments. The natives even told me that it was too bad to drink, and that they only used its water for washing. The well, which is known as the Joti Pershad well, is situated in a somewhat retired position in a recess between two houses opening in front on the road and behind leading by a doorway to a court-yard. The part of the court-yard nearest the well is used as a latrine. A sort of market is held in this court-yard twice a week, and on the succeeding days the smell from the neighbourhood of this well is, I am told, peculiarly offensive. I searched for the typhoid microbe in the water of this well, but failed to obtain a proof of my conjecture. Considering, however, the large num- ber of other microbes that were present (8,000 per cubic centimetre) this is scarcely to be wondered at and is not to be regarded as a proof of the absence of typhoid. To the idea that the presence of typhoid in

dahi may explain the present epidemic the

following objection may be raised:? So far as we know the typhoid microbe is liable

to get into the Joti Pershad well at any season of the year. Human dejecta are 110 doubt al-

ways to be found around the well, and there is a*

Aug. 1894.] HANKIN ON TYPHOID OUTBREAKS. 283

continuous risk of contamination. Why, then, if water-infected dahi is the source of trouble, should both outbreaks in the East Surrey Mess have begun at precisely the same season of the year, namely, shortly after the commencement of the warm season ? Further, it is scarcely likely that the Joti Pershad well ever contains very many typhoid microbes; and as its water pre- sumably is only used to wash the vessels in which the dahi is made, and not to adulterate it, a fortiori very few typhoid bacilli indeed can be left in the vessels in which the dahi is pro- duced. Now, though nothing is, I believe, known with certainty on the subject, it is in the highest degree improbable that a single typhoid microbe can produce the disease; but even if it can, the severity of the cases and the high mortality in both outbreaks in the East Surrey Mess suggest that a considerable dose of the microbe was pre- sent. Supposing it was milk that had been in- fected, the above difficulties would vanish. The

danger of contaminated milk consists in the fact that microbes such as those of typhoid cholera and diphtheria can grow and reproduce in this liquid with extreme rapidity. Consequentl}T, if a single typhoid microbe gets into a pot of milk, several millions may be present after the lapse of a few hours, and the liquid is now

extremely dangerous though at first 'it was

probably harmless, at any rate to a healthy individual. As a general rule disease-producing microbes grow best at the temperature of the blood, and decay-producing microbes grow best at a slightly lower temperature. If milk con-

taining both kinds of microbes is kept at a

relatively low temperature, this condition, toge- ther with the development of decay-producing microbes, will tend to check the growth of such a microbe as that of typhoid. At a high temperature, on the other hand, the typhoid bacillus will have a relative advantage. In this way the connection between the commence- ment of the hot weather and a milk-produced typhoid epidemic might be explained. This

simple explanation cannot be at once applied to the case of dahi, and this for the following reason. In dahi or rather in milk that is under-

going the change into dahi a ferment action

probably followed by a fermentation is taking place owing, as I have shown above, to the

presence of the dahi bacillus. Now it is known that in many cases the fermentation produced by any microbe will, for some obscure reason, hinder the growth of any other species of microbe. It ia therefore possible that the development of the dahi microbe will hinder the development of the typhoid bacillus. In order to test this

point I made use of drop cultures. Ordinary milk is not well adapted for this purpose. It is

advisable to sterilize milk and allow it to stand

for several days, so that the cream should be

thoroughly separated. Then with a capillary,

pipette some of the bottom layer can be taken to make the drops. Minute drops of this liquid were placed on the under-side of coverslips in cells in which they were protected from eva-

poration. On the portions of the< coverslips on which the milk was to be placed, traces of cultures of typhoid, of the dalii bacillus, of the dahi torula, and of dahi itself had previously been deposited. Other preparations were simi- larly made in which typhoid was placed with one or other of the microbes mentioned. In

this way their growth and reproduction could be observed under the microscope. While the dalii torula was found to exert ho appreciable hindrance to the development of typhoid, the dahi bacillus was found to possess such power, at ordinary temperatures. After 24 hours scarce-*

ly any development was to be seen. A spore containing agar culture had been employed to inoculate the milk, and a few spores only had developed into short languidly moving bacilli. Whereas in similar cultures in which no dahi was present much development'X3ould be seen. By ordinary temperatures I mean temperatures between 85? and 90? F. Under these conditions it is impossible for me to use an incubator, and I therefore was unable to try the experiment at any constant temperature. To see the effect of heat on the development of typhoid in dahi, I put a drop culture in a box with a thermometer under a large earthenware vessel in the open air. But after about an hour the thermometer

registered 114? F., so I at once took the box in^ doors and put it in a godown in which the tem- perature was 104?, and during the night fell to a minimum of 95?. At this temperature a very different effect was produced. Even after seven

hours a copious development of the typhoid was observed, and on the next day typhoid bacilli, some in short chains, were freely swimming with their peculiar movement all over the drop and between the much larger and motionless dahi bacilli. The difference in the results of the two

experiments was most clear and decisive, indeed more than I should have expected from the not very considerable differences of temperature in the two cases. From these observations it follows that if the

earthen vessel in which dahi is being made, is contaminated with a trace of typhoid bacilli

during the cold weather, no very serious conse- quences are likely to ensue. If, however, the con- tamination takes place during the hot weather, the trace of typhoid is likely to increase in

quantity and form with the dahi an extremely dangerous mixture; consequently the fact that both outbreaks in the Last Surrey Mess occurred just after the commencement of the hot weather, is not an objection to my theory, but rather affords a slight presumption in its favour. f

In what ways can dahi be-used in European food? I have asked several khansamahs and mem-

284 INDIAN MEDICAL GAZETTE. [Aug. 1894.

sahibs who have very kindly given me the bene- fit of their experience, and find that it may be used with flour as a thickening for white soup, in various Madras curries and entrees; almond

pudding consists of ground-up almonds and dahi baked, boiled or fried, I forget which; cream cheese consists of dahi put in a bag till the liquid has been squeezed out, the residue is then pressed and cut up into cakes. Dahi may, I believe, also be a constituent of various sauces and be employed to adulterate cream. I am

mentioning these matters in such detail not so much in reference to past outbreaks, but with the hope that they may be useful in future, and therefore I should like to dwell on the last point a little longer. Infected dahi ceases to be

dangerous if the dishes containing it have been boiled, for the simple reason that the typhoid microbe is destroyed by heat. Cream cheese and cream adulterated with dahi are especially dan- gerous, because no heat is used in their pre- paration. The process of adulteration of cream as carried

out in Regimental Messes I believe to be as fol- lows, and I venture to commend it to the attention of officers who think that such a thing could not possibly occur. At the same time I must apolo- gize if my hypothetical account somewhat traves- ties the inner working of an Officers' Mess with which I cannot profess to be very closely acquaint- ed. I imagine that the cows are kept or at any rate milked in the Mess compound under the eyes of a Nou-Commissioned Officer. The milkman

makes, say, one seer of cream also under European supervision. He shows it to the Non-Commi3- sioned Officer who sends it to the kitchen. The khansamah gives a written receipt and the milk- man is duly paid. In the meantime a friend of the khansamah's has dropped in for a chat, bring- ing with him one seer of dahi value two annas in a small gurrah. He leaves this behind him, taking away the cream value eight annas. The dahi is then beaten up; a little sugar and a trace of almond essence is added to give it a flavour

resembling that of cream. If the dahi is not

quite fresh it may be slightly sour; if so, this defect can be removed by the addition of a little bicarbonate of soda. A bitter taste which may also be present is of no moment, for the sahibs are certain to ascribe it to the stewed fruit over which the cream is poured. The original cream, for which the officers have paid eight annas, is sold in the bazaar, and no doubt the milkman and khansamah afterwards square up their accounts

demi-officially. Should any of the officers notice that the creamon the stewed fruit is not very good and full of lumps, as has been noticed by officers in the East Surrey Mess, they are not likely to think it worth mentioning, as they know what elaborate precautions are taken in connection

with their dairy. If the khansamah is caught .with the dahi in his possession he will say that

it is for his personal use, and if he further adds that it is impossible to use it in English cookery, or to make anything like cream out of it, he either does not know his business or is telling lies.

There is yet a farther use for dahi which may possibly be a source of danger to British soldiers. Dahi is the basis of many kinds of native sweet-

meats, some of which, as was suggested to me by General Morton, may find their way into bar- racks. On enquiring from several soldiers I learnt that this is the case. In all large canton- ments there are sweetmeat-sellers who manufac- ture sweets on more or less English patterns especi- ally for selling to privates. Some of them (almond cream, cocoanut rock) are apparently made simply by beating up dahi with the sugar, colouring matter, and other ingredients, without the aid of heat, and are, therefore, obviously dangerous. Against others, such as toffee, no such objection can be drawn. These sweets are very cheap and some soldiers eat them in large quantities; in stations where sweetmeat-sellers are forbidden the barracks the soldiers even send out coolies to buy them. These sweets are only to be obtained in cantonments. The soldiers stationed in Agra Fort have no facilities for getting them, and, it may be noted, have been exempt from typhoid. How far is the presence of typhoid in dahi

capable of explaining the two outbreaks in the East Surrey Mess ? In both cases the outbreaks occurred, as above-mentioned, just after the com- mencement of the hot weather. In the 1893 outbreak there were three cases among the officers. They were taken ill within four days of one another, and two of the cases proved fatal. This year four officers and one soldier employed in the Mess developed the disease within a week. Three succumbed. In each case the outbreak in the Mess has been followed by scattered cases among the privates. The near incidence in tim e of the cases in

each outbreak suggests that the cause is to be found in some particular dish rather than in any influence that was acting for a long period. Again, the fact that I found the typhoid microbe in dahi from the Mess is of itself a very strong argument in favour of my theory. It involves the assumption that dahi had been brought into the Mess on previous occasions, which the khan- samah denies, But the story by which he

explained the presence of the sample in question was not without its weak points, and was

repeated with such redundance of detail by the milkman when I interviewed him a few weeks after the incident had occurred, that I think I am justified in regarding it as an effort of the

imagination of the one and of the memory of the other. Perhaps an equally strong argument in favour of my view is to be found in the fact that no other satisfactory explanation has been

Aug. 1894.] JOUBERT ON ABDOMINAL SURGERY. 285

suggested. It must be remembered that the

present is not the first time that typhoid has appeared in the Mess, and consequently such elaborate sanitary precautions have been taken for some time past as to completely exclude the ordinary channels of infection. At the time of the present epidemic, for instance, the milk for the Mess was obtained from cows that were kept in the Mess compound, and milked, fed and watered under European supervision. All water used in the Mess comes from the adjacent muni- cipal standpost, and the khansamah is strictly forbidden to bring anything from the bazaar. The following extract from a Minute kindly sent me by Colonel Hart, C.B., who commands the East Surrey Regiment, in response to a request from me that he would tell me his views on the

subject, shows clearly how completely the origin of the out break had eluded detection:?

" The enteric cases (of last year) rapidly abated when water was first conveyed to the troops by carts, but the cause has not been proved due to water; the water remained under strong suspi- cion, i.e., the water of the filter well; but the renewal of much and virulent enteric fever about the same time this year as last, notwithstanding the new supply of water from the water-works and disuse of the well, lias made it necessary to seek the cause elsewhere.

" This year there are about half the number of men stricken at a time as last year; but the officers have suffered more, four having been stricken, of whom three died.

"Again, the source has not been discovered. The Mess premises have been examined by the medical authorities, and there has never been

any relaxation of the care taken to filter the water and to preserve the milk, the butter, the aerated waters and the kitchens from contami- nation.

"Theories of all kinds have been started by persons not qualified to propound them, such as that the Mess is too near the cemetery; that the Mess-house is built upon some foul spot; that our milk is adulterated with filthy water, and so forth, but these are mere amateur ideas; they are surmises, not demonstrations, and are worth nothing."

I have looked for typhoid microbes without success in both the wells in the Mess compound. I have on a former occasion examined the East

Surrey Regimental sodawater factory and dairy, and believe them now to be both unexceptionable.

I have heard other amateurish suggestions besides those mentioned by Colonel Hart that I do not think worth repeating. In fact it

appears to me that the medical authorities here would have had an admirable excuse for revert- ing to the old-fashioned, grotesque but labour- saving idea that typhoid may be produced by fatigue and exposure without any help on the part of microbes.

Consequently it appears to me that my theory of the dahi remains master of the field, not be- cause I have armed it with many persuasive arguments, but rather owing to the absence of any reputable opponent.

I suppose that in most epidemics, a probable proof as distinguished from an absolute proof of the origin of the infection is all that can be

given. The most' indulgent reader will at best only credit me with having given such a proof of my theory that the typhoid in the East Sur- rey Mess originated from dahi, and no proof at all of my surmise that the same cause has anything to do with the epidemic among the soldiers. If I thought my observations only bore on the out- break in the East Surrey Regiment, I should

certainly have compressed my account of them into much smaller space, but I venture to think that they may have a wider application. Even if it could be shown that the Agra

epidemics have quite another origin, the above account of the natural history of dahi shows that it is a possible source of infection in stations where tj^phoid habitually occurs. If it has been

previously known it certainly has not been widely recognized. I think military officers, when face to face with an unexplained typhoid epidemic, would do well to remember the dahi, before

suspecting their own excellent dairies, their own filter wells, or their own sodawater factories. A moral that may be drawn from this story

is that a standpost in front of your door does not necessarily protect you from the dangers presented by a filthy well a quarter of a mile away. /