Relation of Disease-Bacteria to Milk. 85 



is able to make but slight headway in cattle. This would 

 indicate that the danger of cattle acquiring the infection 

 from man would in all probability be very slight, but these 

 experiments offer no answer as to the possibility of trans- 

 mission from the bovine to the human. Manifestly it is 

 impossible to solve this problem by direct experiment upon 

 man except by artificial inoculation, but comparative ex- 

 periments upon animals throw some light on the question. 



Theo. Smith ' and others 2 have made parallel experiments 

 with animals such 'as guinea pigs, rabbits and pigeons, in- 

 oculated with both bovine and human cultures of this or- 

 ganism. The results obtained in the case of all animals 

 tested show that the virulence of the two types was much 

 different, but that the bovine cultures were much more se- 

 vere. While of course this does not prove that transmis- 

 sion from bovine to human is possible, still the importance 

 of the fact must not be overlooked. 



In a number of cases record of accidental infection from 

 cattle to man has been noted. 8 These have occurred with 

 persons engaged in making post-mortem examinations on 

 tuberculous animals, and the tubercular nature of the wound 

 was proven in some cases by excision and inoculation. 



In addition to data of this sort that is practically experi- 

 mental in character, there are also strong clinical reasons 

 for considering that infection of human beings may occur 

 through the medium of milk. Naturally such infection 

 should produce intestinal tuberculosis, and it is noteworthy 

 that this phase of the disease is quite common in children 



1 Smith, Theo., Journ. of Expt. Med., 1898, 3: 451. 



2 Dmwiddie, Bull. 57, Ark. Expt. Stat., June, 1899; Ravenel, Univ. of Penn. 

 Med. Bull , Sept. 1901. 



3 Ravenel, Journ. of Comp. Med. & Vet. Arch., Dec. 1897; Hartzell, Journ. 

 Amer. Med. Ass'n, April 16, 1893. 



