EFFECTS ON THE ALIMENTARY CANAL 309 



Miller ('22) noted that starvation must be severe to produce marked changes 

 in the gastrointestinal epithelium of albino rats. In cells with atrophic degenera- 

 tion, the mitochondria may be transformed from rod-like to spherical forms, 

 with reduction in number or even total absence. 



Miller ('23) has recently made a careful and extensive study of the gastro- 

 intestinal tract in albino rats severely underfed from birth for various periods 

 (up to 43 days). The tract shows a marked increase in weight (in accordance 

 with the observations of Jackson and Stewart), the increase being relatively 

 greater in the stomach than in the intestine. Measurements also show an 

 increase in the thickness of the mucous and muscular tunics of the stomach. 

 Histologically, there appears a variable (usually slight) edema and regressive 

 structural changes in the mucosa. There is atrophy and degeneration of the 

 surface epithelial cells in restricted areas. The cells show nuclear degeneration, 

 cytoplasmic shrinkage, vacuolation, loss of secretory granules, etc. In extreme 

 cases, the tunica mucosa may be almost completely necrotic. The gastric tela 

 submucosa shows no distinct changes, except occasional hemorrhages. The 

 tunica muscularis shows a variable degree of atrophy with degeneration of the 

 muscle fibers in certain restricted regions only. The various changes are shown 

 by Figs. 82, 83 and 84. 



Ott ('24), in the leopard frog (Rana pipiens) during hibernation and subse- 

 quent fasting with loss in body weight up to 60 per cent, found marked varia- 

 bility in the weight of the empty gastrointestinal canal. The average loss in 

 weight, however, usually appeared relatively much less than that of the whole 

 body, reaching a maximum of 53 per cent in the males and 30 per cent in the 

 females (Table 6). 



Changes during Digestion and Absorption. — Numerous studies have been 

 made of this process, usually involving more or less incidental observations upon 

 the changes in the early stages of inanition (a few hours up to a few days), and 

 subsequent refeeding. 



Ebstein ('70) in dogs fasting 1-4 days found the pyloric glands composed of 

 cylindrical cells with clear (slightly granular) cytoplasm and elliptical nuclei 

 basally placed. Changes are apparent 1 or 2 hours after refeeding, reaching 

 their maximum in 4 or 5 hours. The gland cells become cubical in form and 

 deeply staining; the nuclei become spherical and centrally placed. Heidenhain 

 ('70) also described changes in the gastric gland cells (chief and parietal) in the 

 cat and dog, up to 5 days of fasting. The changes in the herbivora (rabbit, 

 guinea pig, sheep) were found less distinct. Similar results were obtained by 

 Bentkowsky ('76). 



Theohari ('99) studied the changes in the gastric mucosa of the cat, rabbit, 

 guinea pig and especially the dog, in various stages up to 4 or 8 days after feed- 

 ing. The parietal cells during fasting lose the vacuoles found in the early stages 

 of digestion and the fuchsinophile granules are less numerous. Nuclear and 

 granular changes also occur in the chief cells. Stinzing ('99) followed the 

 changes in the chief and parietal cells of the dog, up to 1 1 days of inanition. At 

 the height of digestion (4 hours after feeding) the chief cells are large, the parietal 

 cells small. At the end of digestion (12 hours), the converse is true; the change 



