JANUARY 26, 1912] 
taxonomists, physiologists and ecologists are dis- 
cussed briefly. 
The Deposition of Iron on the Mycelium of an 
Aquatic Fungus: GEorcze T. Moorz, Washing- 
ton University. 
An aquatic ascomycete having peculiar spine- 
bearing spores, which readily germinate, was de- 
scribed. The mycelium from the germinating 
spores soon becomes encrusted with iron in much 
the same way that the so-called ‘‘iron bacteria’’ 
are covered with a deposit of iron. The material 
was particularly favorable for demonstrating that 
the process of iron deposition was not a vital one, 
as has been supposed for the bacteria. 
A New Wood-penetrating Alga: GEORGE T. Moore, 
Washington University. 
An unbranched filamentous alga, with affinities 
with the Cladophoracee was found penetrating the 
cells of a yellow pine board, which had been sub- 
merged in an aquarium for several years. The 
germination of the akinetes and peculiar habit 
of growth was described. 
The Structure and Development of the Colony in 
Gonium: R. A. Harper, Columbia University. 
The 16-celled colonies of Goniwm are formed 
from the mother-cell by definite mosaic develop- 
ment and are thus in sharp contrast with the 
eolonies of Hydrodictyon or Dictyostelium. The 
mother-cell divides by three successive bi-parti- 
tions, the successive planes of division cutting each 
other at right angles. Hach cell of the daughter 
colony occupies the same position in relation to its 
sister cells as it had in the undivided protoplasm 
of the mother-cell. The plane of the first division 
is apparently determined within the cell. The 
different cells of a mother colony divide at all 
apgles with the plane of the colony as a whole. 
‘The changes of position and form which the cells 
of the daughter colonies undergo as they grow to 
mature size are apparently determined entirely by 
relations of adhesion, surface tension, ete. Only 
qualities of the cells as such appear to be trans- 
mitted; the organization of the colony as a whole 
is only indirectly represented in the mother-cell. 
Some Physiological Conditions in the Culture of 
Spirogyra: W. D. Hoyt, Rutgers College. 
A large part of the trouble commonly experi- 
enced in growing alge in the laboratory is prob- 
ably due to the water used, since, in physiolog- 
ieally pure water, Spirogyra was kept in perfect 
condition for several months. The nutrient solu- 
tions of Sachs, Molisch, Knop and Crone were 
tried. The best growth was obtained in Crone’s 
SCIENCE 
153 
solution containing from 0.05 per cent. to 0.1 per 
cent. of total salts. 
As has been shown by others, tap water and 
ordinary distilled water were highly toxic. The 
contained toxic substances were partially or wholly 
counteracted or removed by the addition of some, 
but not all, absorbing substances; by a high con- 
centration of nutrient salts—0.5 per cent. to 1 per 
cent. of total salts; or by great heat. The results 
obtained indicate that the toxie bodies of tap 
water and distilled water were different sub- 
stances; that those of tap water were, in part, 
volatile organic substances; and that those of 
distilled water were largely non-volatile inorganic 
substances. 
A good growth was obtained only when a prop- 
erly balanced solution containing all the nutrient 
salts was used, but the salts of any two of these 
metals gave a better growth than the salt of any 
one metal when used alone. No specific antago- 
nistie action was observed—a mixture of mag- 
nesium and potassium salts seemed just as favor- 
able as a mixture of magnesium and calcium 
salts. 
A colloidal solution of silver was fatal in all 
concentrations as low as 0.0000045 per cent. and 
was injurious in concentrations as low as 
0.000000225 per cent. The addition to the weaker 
silver solutions of a 0.05 per cent. concentration 
of Crone’s solution or of animal carbon produced 
marked improvement in the solutions. A colloidal 
solution of gold was only slightly injurious at a 
concentration of 0.009 per cent., while a colloidal 
solution of platinum of a .0096 per cent. concen- 
tration was not only not injurious during a short 
time, but produced improvement in tap water, in 
a weak colloidal silver solution, and in a solution 
of magnesium sulphate. 
When filaments of Spirogyra were placed in 
colloidal gold or platinum, to which was added 
about 0.015 per cent. NaOH, the outer layers of 
their walls swelled and formed gelatinous-looking 
sheaths which often broke off in crumpled masses. 
These sheaths were not formed in either the 
platinum solution alone or in the NaOH solution 
alone, but were formed when both NaOH and 
either gold or platinum were present. These 
sheaths were deeply colored by the gold and plat- 
inum, while the layers of the wall which formed 
no sheaths remained uncolored. 
The Effect of Light on the Liberation of the Eggs 
and Spores of Dictyota dichotoma: W. D. Hoyt, 
Rutgers College. 
