170 



THE ENERGY OF THE LIVING PROTOPLASM. 



modification is carried still farther by the dense layer of oxygen 

 surrounding the metallic particles. 10 



The katalytic action of mineral acids is evidently also 

 due to a certain motion in the molecules. (2) A motion of different 

 character, however, must be assumed in organic compounds of 

 a certain lability (cf. Chap. III). Usually the katalytic reac- 

 tions are exothermic ones, but in special cases, where other 

 agencies render their aid, also endothermic, as in the action of 

 the chlorophyll-bodies upon carbonic acid in sunlight. 



The katalytic powers of platinum-black are evidently of a 

 very inferior character, compared with the faculties of living 

 protoplasm, — we notice above all an entire want of condensing 

 influence — but in regard to simpler reactions a parallelism can 

 nevertheless be shown to exist, of which I here adduce some 

 further proof. One of the most general synthetical processes is 

 the formation of fat from glucose in living cells, a process 

 consisting in condensation and reduction : 



3 C 6 H ia 0 6 -i6 0 = C I3 H 35 O z 

 (stearic acid) 



C c H I2 0 6 + 4 H = 2 C 3 H s 0 3 

 (glycerol) 



The remarkable transformation of sugar into the higher 

 fatty acids has thus far not yet been imitated, but we can at least 

 obtain lower fatty acids of rancid odour if we mix a 10% glucose 

 solution with about half its weight of active platinum-black ; the 

 odour will be perceptible after 1-3 hours and increase gradually. 

 The main action, of course, is a direct oxidation, but simul- 

 taneously a reduction is going on in other molecules which yield 

 up a part of their oxygen also to glucose molecules under the 

 influence of platinum-black. (3) Neither lajvulose nor cane sugar 

 will yield this result. Platinum-black, also, deprived of its 

 absorbed oxygen in one way or other, is inactive in this regard. 



(1) Platinum-black can absorb 800 times its own volume of oxygen (Doebereiner), 

 but this alone would not suffice to explain its oxidising power, compressed oxygen 

 possessing no increased energy at ordinary temperatures. Cf. also O, Locw, Ber. U. 

 Chem. Ges. 23, 290 and 677, where I gave first the above explanation of the katalytic 

 action of platinum black. 



(2) We will not enter here upon the most recent views in regard to the action of 

 acids, more lif,'ht being still necessary. 



(3) U. Lociu, Ber. Deutsch. Chem. Ges. 33,865. 



