84 THE AMERICAN MONTHLY [May 



elusions of quartz or other impurities but never concentric 

 layers. Fused g-old shows a similar structure. Hence 

 native g"old has not of necessity been in a melted condition. 



Manchester Society. — Papers have recently been read 

 on the slime fung-i, Myxomycetes, antenna of a cranefiy, 

 on the dissection, preparation and mounting- of the radula? 

 of Hyalinia, and on mounting- in g-lycerine jelly. 



Bacteria. — Since 1830, 560 species have become known 

 but only 40 are harmful. Some one says that 250 million 

 could find room on an ordinary postag-e stamp. We take 

 in 30,000 g-erms by respiration each day. They are 

 natures' scaveng-ers but they also g-ive flavor to butter, 

 cheese, beer, g-ame, etc. 



Zeiss Objective. — His 1-lOth inch mono-bromide of 

 naphthalene immersion lens, with numerical aperture 1.60 

 has resolved or made visible a detail l-200,000th of an inch 

 in width. This is the hig-hest limit yet reached. 



Peat. — Peat oi'ig-inates from sphag-num moss usually, 

 thoug-h it may come from heather, lichen or other plants. 

 Its leaves are folded so as to g-ive g-reat capacity for holding- 

 water. Under the microscope is found an adaptation for 

 taking- up water in the spong-y nature of the dead cells 

 lying- between the living- tissues of the leaf, the internal 

 cavities being- connected by canals with the exterior, A 

 sphag-num bog- swarms with desmids, diatoms, protozoids 

 and other low forms of life. 



Protargol. — This is an antiseptic compound of silver and 

 protein. A one-per-cent solution destroys bacteria of 

 anthrax and enteric fever. 



Steel. — With up-to-date micro-photography may be 

 shown the conditions under which the carbon in steel exist. 

 With 1000 diameters mag-nification, steel may be seen to 

 contain minute particles of true diamond. 



Sectioning Bolitic Grains. — A small g-lass slip is laid on 

 a metal plate over a spirit lamp. Soften a drop of nearly 

 dried balsam upon it with heat, lay a plate of mica on it 

 which will become cemented to the g-lass. Upon the mica 

 surface embed in balsam and arrang-e the small objects of 



