414 MISS B. MURIEL BRISTOL ON A 
in use for so many years that it must necessarily stand in preference to 
Monas. 
With the exception of the observation that the fully developed cells of 
Chlorococcum humicola are conocytie *, no further study of this alga has 
been carried out, and our knowledge of the species is limited to Rabenhorst’s 
description given in 1868. Recently, however, an opportunity has been 
afforded for a prolonged study of this alga, and the life-history has proved 
to be far more complicated than Rabenhorst’s description would lead one to 
expect. 
II. CULTURES. 
In October, 1915, a series of cultures was set up with a view to determining 
what algæ, if any, ean live in soil in a resting-state, about 60 samples of soil 
being taken for experiment. In connection with this work, Professor G. 8. 
West very kindly provided a specimen of soil from Kajang, near Kuala 
Lumpur, Malay States, which had first been air-dried and then stored 
in a closed specimen-tube for about two years. Three cultures were made 
from this soil, two in 50 c.c. conical flasks provided with cotton-wool plugs, 
and one in a small glass box. A sterilised mineral salt solution was placed 
in the sterilised vessels and about a cubic centimetre of the soil was 
introduced by means of a sterilised spathula. The cultures were placed 
under a glass jar in a north window, and left to grow at the temperature 
of the room. 
The composition of the culture-solution was as follows, and as evaporation 
took place the eultures were watered with a solution of half the strength. 
Potassium dihydrogen phosphate (KRH,PO,) . . 1:0 gm. 
OCI nirare (NANON. ees AS qe uL vc. 
Oalerum chloride (GR). 22 lale cL. c» e DD. o 
Magnesium sulphate (MgSO)) . . . . . . . 03, 
Sodium chloride (NaCl) Wi eu ee ee ey ys 
Ferric chloride (FeCl;) Xe phan uM. D EM 
Distilled water . . . Ei. lice uo ESTAS 
No growth whatever took place in the cultures until nearly eight months 
after their being set up, but in about the middle of June, 1916, a thin green 
scum appeared round the edges of the culture-fluid. This indicates that the 
initial temperature required for the germination of the alga-spores in this 
Malay soil is very much higher than that required for the germination 
of algæ in this country since cultures of English soils set up towards the 
end of November showed considerable growth by the end of April. The 
alga grew abundantly, forming not only a green gelatinous scum on the 
g 
gr 
* West, G. S., * Algæ, Camb. Bot. Handbooks, vol. i. 1916, p. 211. 
