1897] CURRENT LITERATURE 215 
which the volume before us’ may be considered as a preliminary special part. 
This part is limited to a detailed account of the behavior of certain alge and 
fungi under varied environment. 
In order to study some of these problems it was necessary to develop the 
methods of obtaining pure cultures of alge and . them in vigor as 
well as purity, especially for those species which have no striking character- 
istics at certain stages by which they can be ie identified Both fluid 
and solid media can be used for cultures, and Klebs recommends that both 
methods be used simultaneously. As a nutritive medium fluid he finds Knop’s 
the best. It consists of 
4 parts calcein nitrate, 
I part potassium phosphate. 
In preparing it a concentrated solution (#2) may be made of the last three salts, 
and another (4) of the first. A*proper amount of 4 is to be added to & after 
dilution to the desired percentage. By this method only a small part of the 
insoluble calcium phosphate formed will be precipitated. Solutions containing 
0.2 to 0.5 percent. of salts were found most use 
As solid media one may use either opaque or transparent materials. For 
the former sterilized sand or clay, wet with the nutritive solution, are excel- 
lent. For the latter Klebs, having discarded silicic acid, now uses agar-agar, 
prepared by soaking 0.5" agar-agar in 1o00%™ of 0.2, 0.4, or even I per cent. 
nutritive solution, heating, filtering, and sterilizing. In making pure cultures 
of alge it is necessary to use the same ——— as are required with bac- 
teria and fungi. 
It is impossible to go into the details of the experimentation. Klebs has 
studied various species of Vaucheria, Hydrodictyon utriculatum, tostph 
botryoides, Botrydium granulatum, several species of Spirogyra and Desmi- 
diaceae, Edogonium diplandrum, Ulothrix zonata, Hormidium nitens and A. 
flaccidum, Conferva minor, Bumilleria sicula and B. exilis, Stigeocl 
fenue, Draparnaldia glomerata, Chlamydomonas media, Hydrurus Joctidus, 
Eurotium repens, and Mucor racemosus. Each of these is the sohiuek of a 
ery in + which thie aeeelts - - extended ss, SemENE are set forth. vee 
A. 
experimentation. “Upon the sexual and ‘ies aestinad reproduction of these 
plants Klebs endeavored to determine the effect of such conditions as nutri- 
tion, moisture, light, pemprentets | chemical composition of tite medium, oxy-_ 
gen, and flowing water. 
It is — to see ‘that the determination ¢ of the effect of each factor, i 
