460 INANITION AND MALNUTRITION 



daily of the chronic type) frequently results not merely in a retardation or cessa- 

 tion of growth, but in an abnormal, disproportional growth, which varies greatly 

 according to species, stage of development, type of inanition and other factors. 

 Some parts may show persistent growth at the expense of others, even during 

 total inanition with continued loss in body weight. Likewise in adult fasting 

 animals, regeneration and healing of wounds proceed, though at a retarded 

 rate; and compensatory hypertrophy occurs after the removal of the greater 

 part of the liver (Rous and McMaster), though apparently not in the remaining 

 kidney after unilateral nephrectomy (Sacerdotti). In some species, there is a 

 seasonal, "physiological inanition," during which the gonads develop at the 

 expense of the remainder of the organism. 



The abnormal growth occurring during various types of partial inanition 

 is contrary to Liebig's "law of the minimum or limiting factor," according to 

 which (as narrowly interpreted by some authors) growth should cease when 

 any nutritional factor essential for normal growth is exhausted. Thus the 

 mechanism of growth and development is somewhat elastic. Whatever may 

 be the influence correlating the relative growth of the various organs and parts, 

 this correlation may be markedly changed during total or partial inanition and 

 the process of morphogenesis is accordingly subject to experimental control. 



Underlying Causes. — The question as to why certain cells or organs have a 

 greater resistance to inanition has received various answers. Roux has long 

 held that during inanition those cells persist which happen to require less food 

 in the struggle for existence. This theory was opposed by Schultz and others 

 who claimed that the order of disappearance of the organs (especially in the 

 "reduction" of invertebrates) reverses the order of their appearance during 

 the ontogenetic andphylogenetic development. Another view widely held is the 

 teleologic explanation that during inanition those organs persist longest which 

 are most valuable to the organism or species. Still another (though closely 

 related) view is that the losses of the various tissues and organs are inversely 

 proportional to their functional activity during inanition. 



Stefko ('23a) believes that the degeneration cell changes during inanition are 

 useful to the orgnism, since they set free food material for the surviving cells. 



All these theories, however, appear inadequate to explain the facts observed. 

 Runnstrom (for sea-urchin larvae), Robertson and others have proposed a more 

 rational theory, which would attempt to explain the morphological changes 

 upon the basis of the varying physico-chemical conditions in the starving 

 organism. Cesa-Bianchi ('09) found that the early stages of cell degeneration 

 during inanition correspond to those produced by hypertonic or hypotonic 

 salt solutions, while the later stages resemble those during aseptic autolysis. 

 The characteristic difference in behavior between the lipoidal and the ordinary 

 types of fat is apparently correlated with a fundamental difference in chemical 

 structure. The fatty metamorphosis so frequently observed in cells during 

 inanition may depend upon the exhaustion of the carbohydrates, whose presence 

 facilitates the colloidal protein-fat emulsion in the cytoplasm (Morgulis '23). 

 Robertson ('23a) has recently discussed fully the problem of inanition from 

 the chemical viewpoint. Future investigations along such lines as these will 

 probably give us more satisfactory explanations of the phenomena involved. 



