THE PRESENCE IN MILK OF CERTAIN ORGANISMS 257 



The work above recorded affords indubitable evidence as to 

 the infection of children by the bovine tubercle bacillus through 

 the alimentary canal. 



C. On the Presence of Bacillus Abortus in Milk. A fair number 

 of investigations have been carried out on the presence of Bacillus 

 Abortus in the milk obtained from cows who had aborted in previous 

 pregnancies. The disease is well known, and when it attacks a 

 herd produces serious financial loss. 



It has been shown by numerous observers that the Bacillus 

 abortus is present in the milk of cows both before they have shown 

 any symptoms of abortion and also for a considerable period 

 after the abortion has occurred. The disease, its prevalence, 

 method of infection, etc., was investigated by a special committee 

 appointed by the Board of Agriculture and Fisheries. In con- 

 nection with this committee special investigations were carried 

 out by MacFadyean and Stockman. 



Abortion is produced when the bacillus attacks the uterus, 

 and the investigations were directed towards ascertaining how 

 the disease reached this organ, and infection was found to take 

 place readily by ingestion of the bacillus. In four experiments 

 where the bacillus was given by the mouth three results were 

 positive and one negative, and the committee states : ' With 

 regard to infection by the mouth it is a natural source of infection 

 which until recently did not enter into anybody's calculations 

 regarding the spread of abortion, and knowing, as we do, that the 

 food including the bacillus, and even the feeding-trough, may more 

 or less easily be contaminated on an infected establishment, it 

 seems highly probable that infection by ingestion often takes place. 

 In fact we are inclined to believe that the disease is more frequently 

 contracted in this way than in any other. Presumably the bacilli 

 are absorbed from the intestine and gain the blood stream whereby 

 they reach the uterus. In the case of ewe 77 'the microbe of cattle 

 abortion was found in the cotyledons six days after infection by 

 the mouth.' 



The committee further showed that a large number of animals 

 are susceptible to the disease arising from the Bacillus Abortus, 

 and they produced abortion experimentally in cows, ewes, goats, 

 bitches, and guinea-pigs, and state that Bang also was successful 

 in producing abortion in a mare. 



The committee say : ' Although it is hardly germane to the 

 present enquiry we think it advisable to point out that since the 

 bacillus of cattle abortion is pathogenic for so many species, the 

 possibility of the human female being infected should not be lost 

 sight of.' 



The prevalence of the disease in this country was also investigated 

 by the committee, who found it impossible to ascertain the precise 

 prevalence in the absence of any order requiring the disease to 

 be reported. Information given voluntarily by stock-owners 



