The Microscope. 141 



short time that he had been studying the matter he had already 

 found six chickens, all very badly infested with the bacillus in ques- 

 tion, and he believed that probably 5 per cent of all the fowls 

 offered for sale in this city were similarly affected. It was true that 

 most of the organs thus affected were not used for food, yet, this 

 was not always the case. Danger to the human race of infection 

 fi'om this source was greatly reduced, from the fact that the thermal 

 death-point of the bacillus tuberculosis was about 150° Fahrenheit, 

 so that in the process of cooking thoroughly they would be de- 

 stroyed. A much higher temperature, however, is required to kill 

 the spore's of these bacilli, and, as there could scarcely be a doubt of 

 the existence of spore-bearing bacilli in the chicken, it could not be 

 said that danger from this source did not exist. While, therefore, 

 by no means wishing to assmne the role of the alarmist, the speaker 

 wished to commend the subject to microscopists and the medical 

 fi-aternity, for its interest as well as its importance. Specimens of 

 infected organs of chickens were shown, and mounted slides, show- 

 ing the tuberculous matter and the bacilli themselves, all stained by 

 chemical re-agents, were shown under a number of microscopes. A 

 set of slides illustrative of the subject was donated to the Society by 

 Dr. Stallard, and a vote of thanks was thereupon tendered him for 

 his donation and his interesting address. 



Two interesting slides of native wire copper from Lake Su- 

 perior were handed in by Dr. Selfridge. 



As an instance of the brilliance with which many animal in- 

 teguments are displayed by the use of polarized light, the Secretary 

 exhibited a carbolic-acid mount of the human flea, and also a slide 

 of a rare marine crustacean from the Channel Islands. 



March 23rd. — The committee to which was referred the subject 

 of tuberculous milk, asked to be discharged, as from the great diffi- 

 culty of finding suitable material, it was almost impossible to pro- 

 ceed further in the matter at present. In the specimen of cow's 

 lung which had been submitted as containing bacilli, none had been 

 detected. On motion the committee's request was granted. 



A valuable addition to the Society's already extensive library 

 was made by the receipt of over thirty volumes of publications of 

 the Smithsonian Institution, including all those bearing upon 

 Microscopy. A special vote of thanks was tendered Congressman 

 Morrow for his good offices in procm-ing this donation. 



A very beautiful specimen of crystallized sulphate of baryta, 

 fi-om Derbyshire, England, was received fi'om Thos. Clark, of the 



