80 BACTERIOLOGY 



been carried out upon this subject, and it has been found that 

 there are certain slight differences, e.g. between what may be 

 called the Human, the Bovine, the Avian, and the Cold- 

 Blooded and other Types of the Bacillus ; but the point of 

 greatest importance is that the Bovine, as well as the Human, 

 Type, can and does produce the disease in man. For the methods 

 of differentiation of the bacilli, various cultural, and more 

 especially inoculation, tests are used ; and there are also 

 certain very slight morphological differences. If the bovine 

 bacillus is inoculated into a rabbit's knee-joint, an acute 

 generalised and rapidly fatal tuberculosis occurs. If the human 

 type is similarly injected, the resulting lesions are much less 

 acute, and remain small and few in number and may not kill 

 the animal. In a very valuable series of such experiments by 

 Fraser, 1 in seventy cases of surgical tuberculosis in children, 

 forty-one showed the bovine bacillus, twenty-six showed the 

 human type, and in three cases both types were present. In 

 Edinburgh, abdominal tuberculosis accounts for between 

 three and four per cent, of all the medical cases admitted into 

 the Children's Hospital ; in Glasgow between four and five per 

 cent. The great majority of these abdominal cases are due to 

 the bovine bacillus, and the infection is caused by tuberculous milk. 

 In older persons, especially where the disease affects the lungs, 

 the human bacillus is more usually found, but in adults too, 

 the bovine bacillus also plays an important part. 2 Milk for 

 the feeding of children should therefore, in spite of the 

 foolish prejudice against this procedure in some quarters, be 

 carefully sterilised, though in the future it is to be hoped 

 that a pure milk-supply will be available a condition which 

 is very far from being fulfilled at the present time. 



Amongst cattle, the disease the incidence of which steadily 

 increases with the age of the animal may be communicated 

 directly or indirectly by the discharges from the lesions, 

 whether respiratory, alimentary, or genito-urinary, by the milk, 

 especially in mastitis or udder-disease, and by the excreta 

 contaminating pastures, feeding-troughs, fodder, or milk. 



A vast amount of work has been done in the attempt to 

 produce immunity against the disease. Great numbers of 



1 "The Relative Prevalence of Human and Bovine Types of Tubercle 

 Bacilli in Bone and Joint Tuberculosis occurring in Children." John 

 Fraser, M.D., Assistant Surgeon to the Sick Children's Hospital, 

 Edinburgh. Journal of Experimental Medicine, 1912, vol. xvi. p. 432. 



2 Since the above was written, an important paper by Dr. A. Philp 

 Mitchell, entitled "The Infection of Children with the Bovine Tubercle 

 Bacillus," has appeared in the British Medical Journal for Jan. 17, 

 1914, p. 125, fully emphasizing the truth of this statement. 



