MTOfASIS 83 



conditions. Tn tliis specimen 1)0.4 per cent, of the nitrogen was in 

 an insoluble form, and 9.6 per cent, was soluble. Therefore, over 

 half of all the protein of the liver had been changed into non- 

 coagulable substances in the course of about three weeks (at 37° C). 

 Complete disintejiration of the proteins with liberation of all the 

 amino-acid complexes is probably never readied. Of 45.8 grams of 

 amino-acids present in lOU grams of liver, in ten days ' autolysis there 

 had been set free but 1.85 gm., after 30 days 10.1 gm., and after 50 

 days but 29.1 gm. (Abderhalden and Prym.**) By determining the 

 freezing point and conductivity of autolyzing mixtures, valuable 

 evidence can be obtained as to the rate of change, which, in some cases, 

 is much more significant than the usual estimation of soluble and in- 

 soluble nitrogen (Benson and Wells. ^) Titration of the free amino- 

 acids by formaldehyde, together with the estimation of proteose and 

 peptone nitrogen, also furnish valuable information, while the Van 

 Slyke method of determining free amino-acids is especially useful for 

 this purpose. 



Since Jacoby's paper appeared, the field has been invaded by many 

 workers, who have examined practically every tissue in the bod}', and 

 found that all possess the power of self-digestion ; or, in other words, 

 proteases are present in every cell in the body.'^ The rate of digestion 

 is very different in different organs, however, liver digesting rapidly 

 while brain and muscle tissue digest much more slowly, and the auto- 

 lytic activity varies under different conditions; thus, fever causes a 

 great increase in the proteolytic activity of the muscles/ The char- 

 acter of the antiseptic used modifies greatly the rate, salicylic and 

 benzoic acids giving the most rapid autolysis, while of non-acid anti- 

 septics toluene is perhaps the least inhibitory. One of the most im- 

 portant factors in accelerating autolysis is the H-ion concentration 

 developing in the tissues.*^ Acidity acts, partly, at least, by so modi- 

 fying the substrate that the enzymes can attack it, and a very small 

 excess of acid will destroy the enz^mies ; Bradley '-^ estimates this de- 

 structive acidity at about that concentration of H-ions which is indi- 

 cated by methyl orange and Congo red, the maximum autolysis being 

 obtained with an acidity at about Ph = 6.00. A reaction approxi- 

 mating that of blood (Ph = 7.4 — 7.8) reduces autolysis to a mini- 

 mum. A latent period has been observed before autolysis in vitro 

 seems to begin, part of which time, may be occupied in the develop- 

 ment of sufficient acidity to permit of autolysis, although Bradley's ^'^ 



« Zeit. phvsiol. Chem., 1007 (53), 320. 



7 Jour. Biol. Chem., 1010 (8), 01. 



Ta Except, perhaps, tlic red corpuscles (Pincussohn and Roques, Biocliem. Zeit., 

 1914 (64), 1). 



8 Aronsohn and P.lunientlial, Zeit. l<lin. :Nred.. 1008 (65), 1. 

 8a See Morse, Jour. Biol. Chem.. 1016 (24), 163. 



9 Jour. Biol. Chem., 1015 (22), 113; 1916 (25), 201. 

 9a Jour. Biol. Chem., 1916 (25), 363. 



