254 THE AMERICAN MONTHLY [Aug, 



ments and tortures he had undergone in trying to use the instru- 

 ments horizontally. He worked the instrument with Ilford's 

 plates and in the meeting took photo-micrographs of the para- 

 site of an ox (Hoematopinus eurysternus), of the intestine of a 

 mouse and of a slide of polcystina mounted for transmitted 

 light. He also developed them in an improvised dark room 

 with red light in the presence of the visitors. He then printed 

 positives on glass on Thomas' lantern plates by exposure of 

 three to six seconds at 18 inches from the kerosine lamp, and 

 developed them with the same developer he had used for the 

 ne^jative, but considerably diluted. For these positives he had 

 brought with him negatives of objects previously prepared. He 

 showed slides printed from them, both by passing them around 

 and by projecting them with the society's lantern, with a disc 

 of three feet. 



Monday, April 8, 1895. — Mr. Aitkin read an interesting resume 

 of j)eriodicals recently received by the librarian. The chair- 

 man then called on the lecturer for the evening to read his 

 Note on Micro-fungi and their Air-borne Spores. Mr. Simmons 

 commenced with a brief description of the yeast plant (Torula 

 cerevisise), and explained, with the help of a sheet of diagrams, 

 the method in wMch it is reproduced by budding. The action 

 of the organism in producing fermentation was also dealt with, 

 and the analogy between fermentation in organic fluids and 

 zymotic diseases referred to. He next proceeded to describe 

 three of the commoner forms of mould, viz. : Penicillium glau- 

 cum, Aspergillus glaucus, and Mucor mucedo, which form a 

 greenish crust on old bread, cheese jams, decaying fruit, etc. 

 In an improvised moist chamber, specimens of mould were 

 seen in active growth, and the method of making and studying 

 " drop cultivations " was demonstrated. 



At the close of the lecture, specimens of the yeast plant ob- 

 tained from toddy and of the different moulds referred to, as 

 well as of the spores of fungi and those found in dust, were ex- 

 hibited under the microscope. The session has now closed. 

 The midsummer session will begin with a meeting to be con- 

 vened for July 8, and to be followed by others on August 12 

 and September 9 next. ^ 



