1128 New Yokk State Bueedeks' Association 



tain them is an important factor that has been neglected in many 

 if not most localities. In this country tuberculosis has probably 

 been disseminated through the separated milk and whey from 

 creameries and cheese factories receiving the milk from infected 

 dairies quite as much as by any other means. Kussell of Wis- 

 consin has demonstrated the elhciency of these unsterilized by- 

 products in spreading tuberculosis. In Denmark the separated 

 milk is pasteurized before it is returned to the farm. Other 

 infections such as foot-and-mouth disease are transmitted through 

 the milk. Efforts to prevent diseases of a chronic nature have 

 placed too much emphasis upon the infected animal itself and 

 all too little upon the control of the secretions that arc widely 

 distributed or utilized and which are often the agents for the 

 distribution of the virus. 



Recent investigations tend to the conclusion that the com- 

 municability of the more common infectious diseases with which 

 we have to deal is restricted to individual contact or contact 

 with recently given off secretions, excreta or discharges contain- 

 ing the virus. This tendency adds to the importance of a more 

 careful study of " carriers " among the lower animals. The 

 significance of chronic cases has long been recognized, but the 

 importance of virus disseminators among animals that have re- 

 covered has not been sufficiently emphasized. Specific illustra- 

 tions of this means of spreading the virus and starting up new 

 outbreaks are not numerous where the proof is sufficient to verify 

 the statement. I have ini my personal experience, however, 

 observed fowls that had .suffered from '" roup " or diphtheria and 

 which seemed to be fully recovered, sold and placed in a flock 

 of hens where roup had never been known and where within a 

 short time nearly every fowl in the flock was sufiering from an 

 acute attack of the disease. Li tlio last outbreak of foot-and- 

 nioiitli disease in this country, a calf that liad recovered carried 

 the infection to an entire licrd. Tliese facts are very suggestive 

 iiiid tlicy ])i-iiii;- very vit;il Indies foi- flio snnitariiin and tliose 

 wli(» have to advise tlie buyers of animals. The teaching from 

 the interesting discoveries relative to typhoid and diplitheria 

 " carriers " in the human species are no doubt applicable to 

 several diseases of the lower animals. 



