CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 367 



preserve the infectious principle for moutiis, and in many cases even for 

 a whole year. 



Seventh. That the infectious principle enters the animal organism 

 and communicates the disease more readily through external sores and 

 lesions than through the digestive canal. 



Many experiments were instituted for the purpose of determining 

 upon a system of preventive measures and of testing the value of certain 

 remedial agents. As to the result of these exi)eriments and the conclu- 

 sions deduced therefrom, the reader is referred to the detailed report of 

 Dr. Detmers. 



When Dr. Law closed his former report he had just commenced some 

 important expeiiments for the purpose of determining the susceptibility 

 of other animals to swine plague. These experiments resulted, as he 

 had previously foreshadowed, in the successful inoculation of sheep 

 and rats, and in the transmission of the disease from these animals back 

 to swine in a virulent and intensified form. His first expeiiment was 

 undertaken for the purpose of determining at what period or stage of 

 the malady it is most easily and certainly transmissible from one animal 

 to another by cohabitation. In his previous report an experiment of 

 this kind was furnished, and a deduction made that the disease was 

 most Virulent when at its height, inasmuch as the exposed pig seemed 

 to resist the contagion from an animal in x^rocess of convalescence, but 

 within twelve days fell a victim to the disease when i)laced alongside of 

 a pig in which the malady was rapidly advancing. In the accompany- 

 ing report the necropsy of this 'pig is given, from which it will be 

 observed that it was afflicted with the plague in an intensified form. 



The autopsy of an infected lamb, noticed by Dr. Law in his former 

 report, is also given in full. The intestinal irritation and catarrh, shown 

 in the tenderness of the anus and the mucus discharges accomioanying 

 the feces, together with the elevated temperature and large lymphatic 

 glands, presented much in common with the affection in the pig. The 

 marked eruption in the ears might be accepted as representing the skim 

 lesions, so common in swine suffering with the plague. The more charac- 

 teristic lesions revealed by the post-mortem examination were the purple 

 mottling of the liver, kidneys, and heart, the grayish consolidation of 

 portions of the lungs, and the deep pigmentation of the lymphatic glands 

 in general. 



The next experiment was that of a merino sheep infected by inocula- 

 tion. The record and the results of the autopsy are very similar to those 

 furnish.ed by the lamb. Here, again, the principal changes consisted in 

 purple mottling of the liver and heart, and the deei) pigmentation of the 

 lymphatic glands. Dr. Law is of the opinion that the yellowish-brown 

 coloration of the kidneys in this case implied antecedent changes, i)rob- 

 ably of the nature of inflammation or extravasation. 



From virus taken from these animals Dr. Law successfully inoculated 

 a pig. The pig was inoculated twice, at an interval of fifteen days, with 

 mucus from the anus of the infected sheep, and with scabs from the ear 

 of the lamb. Enlarged lymphatic glands were observable before the 

 last inoculation, and six days after tJiere was a febrUe temperature and 

 the moi-e violent manifestations of the malady. The following cliarac- 

 teristic lesions were revealed by the necropsy, viz : The intestines (con- 

 tained patches of congestion; the follicles were enlarged, and the rec- 

 U\m ulcerated ; purple discolorations were present in the liver, kidneys, 

 and heart ; tJie lynipliatic glands were enlarged and congested by a 

 deep red, in some cases almost black. While the evidence of the pres- 

 ence of the disease in this case was quite positive, in order to confirm 



