EFFECTS OF INANITION UPON ORGANS OF RAT 107 



inanition, which is especially marked in the case of the thyroid 

 gland. The thymus, having already undergone age involution, is 

 affected but slightly, if at all. 



In the second group, which includes the kidneys, hypophysis, 

 heart, testes, lungs, musculature and integument, the loss in abso- 

 lute weight during inanition is more nearly in proportion to that 

 of the whole body, so their relative (percentage) weight is usually 

 not greatly changed. In all except the hypophysis, however, the 

 loss is relatively greater during chronic inanition. Especially 

 the lungs, testes, integument and musculature appear to lose 

 markedly during chronic inanition. 



In the third group, including the spleen, liver and alimentary 

 canal, the loss in absolute weight is relatively much greater than 

 in the body as a whole, so they decrease in relative as well as in 

 absolute weight. The liver and spleen are exceptional, however, 

 in that their loss is apparently relatively greater in acute than in 

 chronic inanition. In fact, in chronic inanition the spleen ap- 

 parently belongs with the second group. 



The variability of the organs as to loss of weight during inani- 

 tion has been explained in two ways: Manassein ('69) noted that 

 those organs which are most active in the organism lose least 

 during inanition. A more rational explanation is that of Pas- 

 chutin ('81), according to whom the various organs lose in pro- 

 portion to their storage content of available food supply. The 

 various proteids, fats and carbohydrates are dissolved and carried 

 away by the circulation at different times and with different de- 

 grees of rapidity. Thus the variability in the loss of weight in 

 different organs and in different types of inanition would be 

 ultimately explained primarily upon a chemical basis. 



SUMMARY 



The principal results of the present paper may be briefly sum- 

 marized as follows: 



1. During both acute and chronic inanition there is apparently 

 a slight increase in the ratio of tail length to body length. This 

 is probably due to a decrease in the trunk length during inanition. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. IS, NO. 1 



