SOME EFFECTS OF COLLOIDAL METALS ON SPIROGYRA!? 
W. D. Hox? 
(WITH FOUR FIGURES) 
The effects of colloidal metals on the activities of living cells. 
seem to have received but little attention, although it appears that 
studies of such effects should yield results of importance to pro- 
toplasmic physiology. We regard protoplasm as largely composed 
of colloidal material, and believe the enzymes affecting many of the 
protoplasmic processes to be colloidal in their nature. Further, 
we know that, outside of protoplasm, colloids affect one another 
in many different ways, and that colloidal metals are capable of 
bringing about reactions which are similar, in many respects, to 
those usually related to the action of enzymes. It becomes a 
matter of considerable interest, therefore, to determine the effects 
of colloidal metals on protoplasm and protoplasmic products, 
especially since the soluble salts of many metals are known to be 
extremely poisonous. The phase of the problem thus suggested 
with which the present paper has to deal may be stated as follows: 
Solutions of the salts of silver, gold, and platinum are poisonous to 
Protoplasm; colloidal solutions of the metals named may bring 
about reactions in non-living materials similar to those caused by 
enzymes; what, then, may be the effects of such colloidal solutions 
on protoplasm ? 
The present investigation was planned to obtain some prelimi- 
oy information bearing upon the answer to this question. It has 
mainly to do with the descriptive aspect of some of the superficial 
effects of colloidal solutions of platinum, gold, and silver on two 
Species of Spirogyra, with a few notes on other algae. The work 
Was undertaken at the suggestion of Professor GEorG Kies, and 
Was carried out in the Botanical Institute of the University of 
in * Botanical contribution from the Johns Hopkins University, no. 30. These 
tans. were carried on while the author held the Adam T. Bruce Fellowship of 
: opkins University. A summary of the results was presented before the 
Society of America at its Washington meeting, December 28, 1911. 
193] (Botanical Gazette, vol. 57 
