TRANSMISSION OF BOVINE TUBERCULOSIS. 209 



he was informed that annually for the last five 3'ears one of the cat- 

 tle had died of tuberculosis in a certain stall. Tlie last one he had 

 the opportunity of examining, which had l)een there but ten months, 

 but had all the symptoms of the malady, greatly emaciated, and 

 troubled with a cough. Dr. Grad's attention was strongly aroused 

 at such a state of things, and to test the matter scientifically he was 

 allowed to select an animal for an experiment. Accordingly he chose 

 from another stable a three-year-old heifer, in calf, that was to all 

 appearances perfectly healthy. She was bred on the farm, had 

 never been unwell, never coughed, and none of her progenitors had 

 ever been affected with phthisis The cow remained quite well until 

 after calving, when a slight cough appeared ; but it increased in fre- 

 quency, emaciation gradually set in, with all the symptoms of tuber- 

 culosis, and in twelve months the creature was a mere shadow 

 of her former self. The evidence therefore in support of tliis mode 

 of infection Grad could no longer resist, as this was the sixth case 

 that had occurred in this stall. Hence he very naturally inferred 

 that the disease was probably- transmitted by the ingestion of tuber- 

 culous matter expectorated by the cattle which had previously occu- 

 pied the place. 



The extension of the malady by cohabitation is, therefore, always 

 liable to occur when animals are so arranged in the stable that the 

 sick and healthy ones can get their heads together, or feed from the 

 same manger. The ha}' may thus become contaminated, and the in- 

 fection takes place through the digestive organs. The expired air 

 also is not untrequentl}' so laden with virulent matter, especially in 

 the advanced stages, that it is not safe for another animal to inhale 

 it. This mode of transmission, which was first suggested by Dr. 

 Morgagni, more than a hundred yesn's ago, and has found many 

 advocates among plnsicians and veterinarians, has now been con- 

 firmed by the experiments of Dr. Tappeiner of Meran, in causing 

 animals to inhale the fine particles of tubercular matter from the 

 air of a room in which the virus had been evaporated by a steam 

 atomizer. Out of eleven puppies experimented on, ten showed well- 

 marked miliary tubercle in both lungs on being killed within twent}'- 

 five to fort}' days — thus proving that this disease is contagious by the 

 breath. 



villemin's investigations. 



In 18G5 Prof. Villemin of the Val-de-grace Hospital, Paris, hav- 

 ing conceived that human consumption in certain cases might be due 



