158 WITHROW MORSE. 



Obviously, there is no acceleration, but rather an apparent 

 inhibition, which is not a true inhibition of digestion rate, but is 

 due to the fact that autolysis has proceeded in these tissues before 

 the death of the larva, the products being withdrawn by the 

 circulation, leaving only the slowly autolyzing tissues for this 

 experiment. The apparent increase of 1.68 g. over 1.07 g. in the 

 case of the non-protein nitrogen figure, is insignificant, while the 

 difference in non-protein and amino nitrogen is due to peptones 

 and other polypeptids. 



The tissues, then, are not in more favorable condition for self- 

 digestion in the case of atrophying than in normal instances. 



The question arises as to whether the enzyme content varies 

 in the two cases. This is improbable. Loevenhart (17) has 

 shown that in liver atrophy in mammals, an ester splitting en- 

 zyme, esterase, is not increased over that of the normal liver. 

 Bradley (18), again, has shown that in the mammary gland there 

 is no increase in lipase during lactation over the resting condition 

 of the gland. Finally, the writer (19) has interpreted his experi- 

 ments upon atrophy similarly. However, the following experi- 

 ment seems to demand that, if it is true that the atrophying 

 tissues themselves do not digest faster in vitro than non-atrophy- 

 ing masses, there is something in the enzyme relations in the 

 two cases which is different. 



Experiment. Four tenths of a gram of tissue, wet weight, from 

 a non-involuting larva were placed in 3 c.c. of serum from an 

 adult frog. Toluene was added. A control consisting of 0.4 c. 

 of involuting material was made. Digestion was permitted at 

 30 C. for 24 hours. Each preparation was then diluted to 5 c.c. 

 of fluid with distilled water. 2.5 c.c. aliquots were examined for 

 amino-nitrogen by the gasometric method of Van Slyke: 



Control 0.63 mm. Ntb nitrogen per 0.4 g. tissue. 



Absorbing 1.19 



Here, the differences are approximately 1 :2 and inasmuch as 

 we have seen that there is probably more autolyzable material 

 taken from the involuting tissue, which has undergone a certain 

 degree of self-digestion or atrophy (compare the preceding experi- 

 ment), leaving less to digest in artificial autolysis experiments, 



