370 COLLOIDS IN BIOLOGY AND MEDICINE 



sterile, so that incidental bacterial growths are not the cause; it is 

 brought on by a series of different enzymes each of which has a definite 

 function, and the process is called autolysis or autodigestion. 



All the hydrosols investigated, namely, those of silver, gold, plat- 

 inum, mercury, palladium, iridium, copper, lead, ferric hydroxid 

 and aluminium hydroxid have the ability to assist autolysis; M. 

 ASCOLI and his coworkers, by separately investigating the resulting 

 products, were able to determine the action of the individual enzymes. 

 For instance, the liver of a recently killed animal was cut up into small 

 pieces and passed through a sieve; it was then diluted with water and 

 distributed in a number of sterile vessels with 1 per cent toluol to pre- 

 vent putrefaction. In one sample the albumins were immediately 

 coagulated, and the total nitrogen, as well as the individual nitrogen 

 fractions, determined. Varying quantities of metal hydrosol were 

 added to the remaining vessels and they were kept for 72 hours at 37 C. 



Each portion was then tested for 



1. Total nitrogen (according to KJELDAHL). 



2. Nitrogen (as monamino acids) . 



3. Purin-bases (according to SALKOWSKI). 



4. Albumose-nitrogen (according to BAUMANN and BOMEE). 



The difference between the total nitrogen and the sum of the other 

 values gave the quantity of nitrogen present as diamino acids, peptone 

 and ammonia. 



In general, there is an accelerating action on the total autolysis 

 as well as on the cleavage of the nucleins, and the formation of 

 monamino acids; though there are considerable quantitative dif- 

 ferences between the different hydrosols. For instance, minimal 

 quantities of Ir, Hg, Cu and Ag favor the autolytic process in 

 general, yet decidedly larger quantities of Pb, Au, Pt and Pd are 

 required for this purpose. The same facts hold for the formation of 

 monamino acids. Small doses increase, while larger quantities of 

 hydrosols interfere with the cleavage of nucleins; however this 

 does not hold true for silver, platinum and gold hydrosols. Under 

 ordinary circumstances the uric acid formed during autolysis is 

 broken down still further by a uricolytic ferment; the action of this 

 ferment is inhibited by silver hydrosol. 



Though there is no difference between the action of stabilized and 

 unstabilized silver upon autolysis, such a difference was noticeable after 

 the addition of defibrinated blood. Defibrinated blood interferes with 

 the acceleration of autolysis due to unstabilized silver hydrosol, but 

 it does not do so in the case of the stabilized hydrosol. 



This observation is also of great interest in connection with the 



