OOTOBEE 12, 1900.] 



SCIENCE. 



555 



This action of platinum depends on its 

 fineness of subdivision, and the difficulty of 

 obtaining it of uniform quality in this re- 

 spect has hitherto prevented the extension 

 of experiments to the quantitative stage. 

 Eecently, however, Bredig has succeeded in 

 obtaining a colloidal solution of metallic 

 platinum by volatilizing the metal in an 

 electric arc under water.* In this form the 

 metal exposes an enormous surface, and is 

 capable of being measured volumetrically, 

 and the introduction of quantitative experi- 

 ments is now possible. As little as one 

 gram-atom f of colloidal platinum diffused 

 through seventy million liters of water 

 shows a perceptible action on more than a 

 million times the quantity of hydrogen per- 

 oxide. What I wish to point out as especi- 

 ally interesting in the work of Bredig and 

 von Berneck is this: they find that relatively 

 minute portions of certain substances are 

 able to inhibit the action of the platinum, 

 and that these are substances which exert 

 a markedly poisonous efiect on the living 

 cell and on enzymes. 1/345,000 gram 

 molecule per liter of hydrogen sulphide 

 already exerts a strongl}^ restraining action, 

 1/1000 gram molecule of hydrocyanic acid 

 per liter stops it entirely, and much less is 

 able to retard it greatly. Carbon disulphide 

 and mercuric chloride show a similar be- 

 havior. All of these substances are power- 

 ful poisons, and Bredig uses the very ex- 

 pressive word ' poisoning ' with reference 

 to their restraining action on the platinum ; 

 the platinum is ' poisoned ' by hydrocyanic 

 acid. Here we have a complete parallel 

 with what is observed in the organism, and 

 the parallel suggests a similar cause. The 

 platinum acts towards hydrogen peroxide 

 as a toxine, and the hydrocyanic acid as an 

 antitoxine; or conversely, the metal may be 

 compared with a natural ferment, the acid 

 to a toxine which inhibits its action. It is 



*ZeU. Physik. Chemie., 31. 271. 

 1 193 grams. 



not impossible that such studies, conducted 

 with purely inorganic bodies, may help to 

 throw definite light on the nature of im- 

 munity. At least we may hope that the 

 study of catalysis, using simple substances 

 under conditions admitting of exact meas- 

 urement, will help to solve some of the 

 deepest problems of physiology and dispel 

 the ignorance which hides itself under the 

 name of vitalism. 



Time is wanting to consider at any 

 length the newer relations of organic chem- 

 istry to the theory of valency, especially in- 

 teresting among which is the attempt of 

 Werner to show that the supposed constant 

 tetravalency of carbon is simply a partic- 

 ular phase of a general law of combination 

 which does not come under the current 

 valence doctrine. I may mention also that 

 Nef regards many peculiar reactions as due 

 to the existence of a bivalent condition of 

 carbon, which we have hitherto recognized 

 only in carbon monoxide. So important, 

 indeed, is bivalent carbon, according to this 

 savant, that he expresses the conviction 

 ' ' that in the chemistry of methylene is to 

 be found a future exact scientific physiology 

 and medicine and perhaps an explanation 

 of the vital processes."* If this be true, 

 physiological chemists cannot be too prompt 

 in abandoning all other investigations for 

 the study of bivalent carbon. 



I have alluded to but a few features of 

 the more recent progress of organic chem- 

 istry, and pointed out some of its newer 

 tendencies. Slow as this revival is, there 

 can be no question that the trend is away 

 from a too narrow contemplation of the 

 formula as a final end of study, and towards 

 the deeper consideration of nature as the 

 manifestation of energy. There can be no 

 question that the continuity of all classes 

 of chemical phenomena will be more and 

 more recognized. Within a few years we 

 have seen a new kind of chemistry come 



* Liehig's Annalen, 298. 374. 



