June 9, 1887] 



NA TURE 



127 



Now, mark this, that on one particular day the fever 

 broke out. We will return presently to this point. 



As an illustration of the second kind (viz. probably not 

 from a human source), I will refer to the outbreak of 

 scarlet fever in Oxford in the spring of 1882, recorded by 

 Dr. Darbishire in the St. Bartholomew's Hospital Reports, 

 vol. XX. 



The substance of Dr. Darbishire's Report is this:— Three 

 cows were kept by those who sold the milk, and nine 

 houses, containing eighty-five persons in all, were supplied 

 morning and evening ; the milk was never stored, as there 

 was generally barely enough at each milking for all the 

 customers. In the house to which the cows and paddock 

 belonged, there was a case of diphtheria in a young lady. 

 She was removed to the infirmary on March i. The cow- 

 man had a child ill with scarlet fever in his cottage from 

 February 27 till March 3. Cn March 3, Dr. Darbishire 

 had this child removed to the hospital and the cowman's 

 cottage thoroughly disinfected ; the cowman left his 

 cottage to sleep in lodgings near, the care of the cows 

 having be :n handed over to another man, engaged for 

 that purpose. Now, if the milk had become infected from 

 either of these two cases (one diphtheria and the other 

 scarlet fever), this must have occurred for the first before 

 March i, for the other before March 3 ; and as the period 

 of incubation of scarlet fever is known to be as a rule less 

 than seven days, it follows that March 3, being the last 

 day on which the milk could have received the contagium 

 from a human being, March 10 would be the last day on 

 which scarlet fever could have been produced by that 

 milk, and the majority of cases of scarlet fever must have 

 occurred before that day, as one cannot assume that in 

 all these cases the period of incubation was protracted to 

 such length as seven days. But mark what really did 

 happen. Dr. Darbishire states that no case occurred till 

 March 10, on which day 2 cases of sore thro it and i case 

 of scarlet fever occurred ; on March 11, i case of sore 

 throat ; March 12, 2 of sore throat and i of scarlet fever ; 

 March 13, 4 of sore throat and 2 of scarlet fever ; March 

 IS, I of sore throat and i of scarlet fever ; March 16, 2 of 

 sore throat and i of diphth3ria ; March 17, i of sore 

 throat ; March 18, i of sore throat. 



Now, all these cases were proved by Dr. Darbishire to 

 have bsen caused by that milk. There occurred subse- 

 quently other cases, but these were traced to have been 

 due to secondary infection from person to person. 



This is a good illustration of a milk epidemic, in which 

 the milk most probably did not receive the contagium by 

 human agency. And there are other milk epidemics 

 which on analysis of dates lead to the same conclusion. 

 The infection of this milk was probably brought about as 

 I shall show you hereafter in some other way. 



As an instance of the third kind, viz. where milk has 

 clearly not been infected from a human source, I will refer 

 to Mr. Power's Report in 1882 on an epidemic outbreak 

 of scarlet fever in St. Giles and St. Pancras. " The disease 

 was distributed with a milk service derived from a Surrey 

 farm. In this case two facts could be affirmed : the one 

 that a cow recently come into milk at this farm had been 

 suffering from some ailment, seemingly from the time of 

 her calving, of which loss of hair in patches was the most 

 conspicuous manifestation ; the other that there existed 

 no discoverable means by which the milk which had 

 coincided with scarlatina in its distribution, could have 

 received infective quality from the human subject." 

 (Medical Officer's Report for 1885-86, pages v. and vi.) 



The Medical Department of the Local Government 

 Board, have from these facts drawn the conclusion that 

 " distrust must be placed on the universally accepted 

 explanation that milk receives infective properties directly 

 by human agencies," and further that " the question of 

 ris'v from specific fouling of milk by particular cows, suf- 

 fering, whether recognized or not, from specific disease, 

 was seen to be arising." This view received striking 



confirmation and proof by a report of an outbreak of 

 scarlet fever that occurred at the end of 1885, and the 

 beginning of 1886, in the North of London, which was 

 investigated by Mr. Power ; his report is published in 

 extenso in the Report of the Medical Officer of the Local 

 Government Board for 1886. I will here give you the 

 substance of it. Mr. Wynter Blyth, Medical Officer of 

 Health for Marylebone, " had last December observed 

 a sudden outbreak of scarlatina in his district to be 

 associated with the distribution of milk coming from a 

 farm at Hendon, and had found reason for believing that 

 the disease had prevailed exclusively amongst customers 

 furnished with milk from that source." Mr. Power on a 

 more extended inquiry found that a similar prevalence of 

 scarlatina had occurred about the same time in other 

 parishes in and near the metropolis that were furnished 

 with milk from the same farm By careful inquiry, Mr. 

 Power could with certainty exclude any contamination of 

 the milk from a human source, or that anything of the 

 kind known as " sanitary " conditions could have had any 

 concern with the infectivity of the milk. Mr. Power 

 showed conclusively that only certain sections of the 

 milk-supplies of this farm, and finally only certain cows 

 from which these sections of milk were derived, had any 

 relation to the observed results. " In the end," says the 

 Medical Officer, " he has demonstrated, beyond reasonable 

 doubt, the dependence of the milk scarlatina of December 

 on a diseased condition of certain milch cows at the 

 farm — a condition first introduced there in the previous 

 month by some animals newly arrived from Derbyshire ; 

 and he finds strong circumstantial evidence for believing 

 that the later phenomena of this dependence were brought 

 about through the extension of the diseased condition of 

 one set of animals to another set, after the fashion of an 

 infection." 



Now this disease, as it presented itself in some of these 

 Hendon cows, consisted in the presence of sores in 

 different parts of the skin with loss of hair in patches, 

 ulcerations on the udder and teats, and a visceral disease, 

 notably of the lungs, liver, kidney, and spleen, which, 

 although milder in character, very much resembled the 

 visceral lesions occurring in cases of human scarlet fever. 

 By experiment it was shown that the matter of the ulcers 

 of the udder is possessed of infective power, inasmuch as 

 on inoculation into the skin of calves the same ulcers are 

 reproduced ; further, it was shown that in the ulcers of 

 the cow there existed in large numbers a species of micro- 

 coccus, which, on being planted on artificial nutritive 

 media, such as are used for the study of bacteria, produces 

 in a few days a crop of micrococci, possessed of very 

 distinct characters by which they are distinguishable 

 from other bacteria. 



When calves are inoculated from a cultivation of this 

 micrococcus, they become, after an incubation period, 

 affected with a cutaneous and visceral disease the same 

 as the disease of the Hendon cows. From the blood of 

 these animals the same microbe was recovered by cultiva- 

 tion. 



To sum up, then, it has been shown that at this Hendon 

 farm there existed certain cows affected with a com- 

 municable disease which, in many points of its pathology, 

 bears a great resemblance to human scarlatina ; further, 

 that the milk of these cows gave scarlet fever to human 

 beings ; and, lastly, that a particular microbe was obtained 

 from these cows, which in calves produced a disease 

 similar to the one from which those cows were suffering. 

 In order to complete the evidence thus far obtained, it 

 was necessary to prove that scarlet fever in man is due to 

 the presence and multiplication in the blood and tissues 

 of the same micrococcus, and that this microbe, if obtained 

 from human scarlet fever, produces in the cow the same 

 disease as is produced by the micrococcus of the Hendon 

 cows. Now, this proof has been satisfactorily given. In 

 the first place, it has been shown that in the blood and 



