126 BIO-CHEMICAL JOURNAL 



be built up into the bioplasm, and held there in a form in which they 

 could be readily eliminated for the supply of the energy needs of the 

 organism, as demanded by the hypothesis of Pflilger, it should be 

 possible to detect variations in the immediate post-mortem changes in 

 the tissues, according to whether such tissues are derived from animals 

 during digestion, or during a period of fasting. It was assumed that 

 tissue of an animal with nitrogenous matter stored ready for elimina- 

 tion for the supply of energy needs, should show a more rapid 

 post-mortem change than tissues derived from an animal during a 

 period of fasting. 



With the exception of the small intestine, which will be discussed 

 in detail below, it was found, in the researches carried out in conjunc- 

 tion with Miss J. E. Lane-Claypon, 5 that but small change took place, 

 as far as the nitrogen at any rate was concerned, during the first four 

 hours of incubation with water ; but that, in the case of the liver, after 

 this so-called 'latent period,' a rapid degradation of the albumen set in 

 (lasting generally from 4-6 hours), the rate of which depended on the 

 state of nutrition of the animal at the time of death. This autolysis 

 was more rapid in the case of the fasting than of the fed animal the 

 reverse of what might be expected if the hypothesis of Pfluger be 

 correct. From the results obtained it appeared that the autolytic 

 enzyme functioned by acting when the energy needs of metabolism 

 were not satisfied by the food-stuff ingested. The results also 

 furthered the hope that this method of research might be available as 

 a general method for the study of metabolism. It was tested 6 by being 

 applied to a special case of abnormal metabolism, viz., when animals 

 are fed with thyroid glands, and results parallel in every respect with 

 those got by other methods were obtained. 



What is the mechanism now by means of which this autolytic 

 enzyme acts ? Does it exist in the tissue as a zymogen, from which the 

 enzyme is liberated by the means of a kinase-like body, as in the case of 

 trypsinogen, or is it always present in the tissue, but is prevented from 

 acting during periods of full nutrition by the presence of inhibitory 

 bodies derived from metabolites, which gradually disappear after 

 ingestion of food ? 



