424 



SCIENCE 



[N. S. Vol. XXXVII. No. 950 



denser, but no attempt at ultra-filtration, 

 which might easily have been done by using 

 collodion as Schoep' has done, was made, for 

 I was not concerned in these experiments with 

 the size of the particles. The solutions were 

 found to be quite active and little or no de- 

 posit of the coagulated platinum [" sponge "] 

 was obtained, which, of course, is not active 

 catalytically to the extent to which platinum 

 black is. I have tried colloidal iron in some- 

 what similar experiments, but it is assuredly 

 not to be expected that this colloid would give 

 results with living things, on account of its 

 low activity as an inorganic catalyzer. The 

 gutta percha was dissolved in ether and 

 emulsified by water and alcohol, and then the 

 whole mass was dialized through fish-bladder 

 for three months to remove the alcohol and 

 ether. It was examined before using, to de- 

 termine the activity as far as the Brownian 

 movement could be taken as a criterion. 



Paramecium, Stenior, Blepharisma, Eu- 

 glena, Phacus and diatoms, Ceratium and 

 other desmids were used as material, but more 

 exact work wa^ done with Paramecium and 

 Stentor. One set of experiments consisted in 

 isolating individuals of these species and ma- 

 king drop-cultures of them in a small amount 

 of the colloidal solution; a second series was 

 conducted in salt dishes, where the amount of 

 colloidal solution was about 2 cm°. I ran 

 checks with tap-water. 



It was to be expected that the platinum so- 

 lution, at any rate, would prove to be toxic, 

 but this was not the case, for the organisms 

 lived without any suggestion of being in an 

 unwholesome medium; the same was true for 

 the gutta-percha solution. The rate of cell- 

 division was noted, comparing that of the in- 

 dividuals under experimentation with that of 

 the checks. The rate was found to vary in no 

 appreciable manner. One variable may have 

 been introduced, and that was food, but I 

 could not devise any way of eliminating the 

 difiiculty. Bacteria were present in aU of the 

 solutions and, of course, in the medium of 

 the control experiments. The bacteria were 



'"Uber ein neues TJltrafilter. Wo. Ostwald's 

 KoUoid-Zeitschr., " Bd. 8, p. 80, 1911. 



kept down appreciably by keeping the dishes 

 in strong light, but this did not eliminate 

 them. 



From these experiments, which are by no 

 means exhaustive, I conclude that the inor- 

 ganic catalyzers, such as I have used, are not 

 effective in appreciable manner on protoplasm. 

 It may well be that protozoa are not affected, 

 while other organisms, or portions of other 

 organisms, may be. As an instance where 

 protozoa are not affected by an agent that is 

 markedly effective in inducing cell-division 

 in certain tissues in higher forms, I may men- 

 tion the power of certain azo-compounds, 

 notably Scharlach E, to cause proliferation of 

 epithelium in mammals, so that they have 

 been introduced into dermatology for treat- 

 ment of burns on the skin, and it has been 

 noticed that workers in anilin factories' show 

 thickenings of the skin caused by contact with 

 the dyes. I have grown Paramecium in drop- 

 cultures with granules of Scharlach K, which 

 were seen to enter the bodies of the organisms 

 and to occur in the food vacuoles, but there 

 was no evident increase either in the size of 

 the organisms or in their rate of fission. Ob- 

 viously, the dye is not responded to by proto- 

 zoa as it is by epithelium; perhaps this spe- 

 cific response is somewhat similar to condi- 

 tions in experiments with inorganic catalyzers. 

 In these experiments, both a suspensoid [col- 

 loidal PI and an emulsoid [gutta percha] 

 were used. It is to be remembered that the 

 study of inorganic catalyzers has been car- 

 ried on principally with the latter group, but 

 this does not mean that the former one is not 

 promising, or for a priori reasons should not 

 be expected to give results, except in so far 

 as it does not follow the criterion of Emil 

 Fischer" of a stereochemical relation, wherein 

 enzymes of whatever nature are defined as 

 optically active catalyzers; platinum black is 

 not optically active, which may account for 

 its inability to influence organisms. The 

 same may be said of the gutta-percha solution. 



P. S. — Since the above account of my experi- 

 ments was written, there has appeared a very 



' See Sachs, Wien. IcKn. Wochen^chr., Bd. 24. 



"CTem. Ber., Bd. 27, S. 3230. 



