1914] 
SCHRAMM—PURE CULTURE METHODS IN THE ALG/E Ж 
concerned, the authors state that it is necessary to begin with 
the zoóspore, as a pure culture from filaments is extremely 
difficult to obtain. Му own experience does not bear out this 
statement in all eases as it was found that especially among 
the Ulotrichales pure colonies were regularly and easily obtained 
from filaments. 
Artari in 1902 (2) reports the isolation of Chlorococcum 
infusionum and Scenedesmus caudatus in pure culture. Chick 
(7) attempted to isolate Chlorella pyrenoidosa through the use 
of sterilizing agents such as hydrogen peroxide and sunlight. 
These trials, however, did not prove successful, as the alga 
failed to show a resistance sufficiently greater than that of 
the bacteria to make possible a successful separation. Тһе 
isolation was finally attained by placing a few drops of water 
containing the organism on a sterile synthetic agar plate, and 
spreading the same over the surface with а brush. Тһе same 
brush was used to distribute sterile water drops over the surface 
of other plates, no additional algal material being added. 
From the later dilutions pure colonies were obtained. Frank 
(10) was unable to obtain pure cultures of Chlamydomonas 
tingens by the agar plate method. 
Jacobsen (11) reports the isolation of Chlorogonium and 
Polytoma in pure culture. This author made use of an inter- 
esting method of separation of algal species based on their 
different degrees of resistance to drying. Discs of filter paper, 
on which drops of water containing Spondylomorum and 
Chlamydomonas variabilis had been placed, were dried in an 
incubator at 28°C. After twenty-four hours, the discs were 
placed in a suitable medium, but only the Chlamydomonas 
species developed, Spondylomorum having been killed. Chlo- 
rogonium euchlorum and Polytoma uvella also showed themselves 
very sensitive to drying, whereas Chlamydomonas usually sur- 
vived the desiccation. Old cultures of Chlorogonium euchlorum 
proved to be very resistant owing to the presence of zygospores 
which had been formed by the conjugation of gametes. 
While reference might be made to a number of other inves- 
tigations which deal in an incidental way with pure culture 
technique, it is believed that those given will serve to indicate, 
in a general way, the present status of the subject. (For further 
