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 cranefly, 

 on the dissection, preparation and mounting- of the radulae 

 of Hyalinia, and on mounting- in glycerine 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' scavengers but they also give 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 1-200, 000th of an inch 

 in width. This is the highest limit yet reached. 



Peat.— Peat originates from sphag-num moss usually, 

 though it may come from heather, lichen or other plants. 

 Its leaves are folded so as to give great 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 

 sphagnum 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-photog-raphy may be 

 shown the conditions under which the carbon in steel exist. 

 With 1000 diameters magnification, 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 



