SECRETARY'S REPORT. 23 



twenty-four hours. Each of the Maine cows were similarly 

 exposed. The two cows brought from Ashby were then killed, 

 and found to have been diseased with contagious pleuro- 

 pneumonia. The lungs of one were but sliglitly affected, but 

 the other had a large portion of one lung diseased. No other 

 animal of Smith's herd, except one cow, was as badly affected, 

 the lung on one side weighing twelve pounds, on the other a little 

 over two pounds. In about forty days Dr. Thayer decided that 

 one of the exposed cows had the disease, and expressed an 

 opinion that two others would have it. Two other veterinary 

 surgeons were quite confident that three of the four cows had an 

 adhesion, but Dr. Thayer has never given it as his opinion that 

 more than one has had pleuro-pneumonia. 



Owing partly to an indisposition on the part of a majority of the 

 Commissioners, and partly to a difficulty to find a suitable place, 

 no more cows were exposed till the fourteenth, after the cow at 

 Newtonville was taken sick, when she was carried to Weston and 

 exposed for several 'days to two cows brought from Upton, and 

 after the exposure taken back to Newtonville. Neither of the 

 Upton cows had shown any symptoms of the malady up to the time 

 the disease was discovered on Deer Island, (nearly three months,) 

 and it was thought best to expose them to an animal from that 

 herd. Accordingly, Dr. Thayer selected an animal which he pro- 

 nounced perfect for the purpose, had it carried to Newton and 

 exposed the cows there to his satisfaction, when the animal was 

 killed and found to have had the disease in its worst form. It 

 is supposed that there has not been sufficient time since the last 

 exposure to indicate the effect.* 



To sum up the result, we have exposed in the manner 

 I have stated six cows ; one only has had the disease ; 

 three of tliem have had the double exposure of having 

 two cows affected with the disease tied on either side of 

 them for twenty-four hours, in such a manner as to make it 

 certain that they should inhale the breath of the sick ones, eat 



* Since writing the foregoing, I learn from Dr. Thayer that the " Uptftn 

 cows" were exposed to the animal from Deer Island for two weeks, it having 

 been tied between them during the whole of that time. Sixty days have passed 

 since, and neither of the cows has shown any evidence of having had the disease, 

 unless a slight cough in one of them may be considered such. Forty-five days 

 is the extent of time fixed upon as the time of incubation. 



