19 



of the infected milk by injectiou iuto the abdominal cavity of guinea- 

 pigs with the usual precautions. His results were as follows : 



1. Milk was used five times from cows affected with a high degree 

 of general tuberculosis in all the organs. 



2. Milk was used six times from cows with only a moderate 

 degree of disease. 



8. Milk was used nine times fiou) cows in which the disease was 

 localized in the lung. 



From these twenty cases the milk was proven to be infectious in 

 eleven. The percentage of positive results in the animals when ar- 

 ranged in accordance with the three groups above given was 80 per 

 cent, in the first group (milk from cows in a very advanced stage of 

 the disease), 66 per cent, in the second group, and 33 per cent, in the 

 third. He found the bacilli in only one of the specimens of the milk, 

 and considers that this, therefore, shows that the inoculation exper- 

 ime.its are the more certain guide as to whether the milk is infectious 

 or not. 



These results are extremely interesting, although they do not lay 

 as much stress as do mine upon the presence or absence of lesions of 

 the lacteal tract. 



The experiments which I am able to report* have been made pos- 

 sible by the liberality of the Massachusetts Society for Promotino- 

 Agriculture, which became interested in the question some time ago, 

 and has put it in my power to carry them on. They have given 

 everything in the way of pecuniary and moral support that the work 

 has required ; my own part has been that of general director, and I 

 liave had associated with me during the whole time the Society's vet- 

 eiinarian, Austin Peters, U.V. 8. For the last year I have also had the 

 very valuable aid of Dr. Henry Jackson and Langdon Frothinoham, 

 M. D. V. 



All of the inoculation experiments and most of the microscopic 

 work have been done in the bacteriological laboratory' of the Harvard 

 Medical School, some of the microscopic work at the Society's labo- 

 ratory in Boston, whilst the feeding experiments have been done and 

 the experimental animals have been kept at a farm in the country 

 devoted to this especial purpose, and situated among the healthiest 

 possible surroundings. Nothing has been set down as the result 

 of microscopic observation that I have not myself verified, and 

 every portion of the work has been carried out under the most 



* The full notes of these experiments will be found in the Transactions of the Associa- 

 tion of American Physicians, vol. iv., 1889. 



