70 INANITION AND MALNUTRITION 



inanition, with deficiencies in proteins, salts, etc. may be endured for various 

 (usually much longer) periods of time, to be mentioned later. As to age, the 

 young are much less resistant than adults, as will be discussed later. Among 

 animals, the carnivora endure inanition longer than the herbivora, the cold- 

 blooded longer than the warm-blooded, and, in general large animals longer than 

 small animals. Individuals with large amounts of stored food reserves, espe- 

 cially of fat, can endure starvation for longer periods. Exercise, exposure to 

 extremes of temperature, infections, etc. are unfavorable factors. 



In general, all factors are effective in proportion to their influence upon 

 metabolism. An increased rate of metabolism will more rapidly exhaust the 

 stored food reserves, or reduce them below the necessary minimum, with resultant 

 death from starvation. On the other hand, a lowered rate of metabolism dur- 

 ing inanition will prolong the period of endurance. This, together with the special 

 provision of food reserves, makes possible the extensive periods of inanition 

 during hibernation and some allied conditions of "physiological inanition" 

 (cf. Alexandre '88, '89). 



Loss of Body Weight in Adults. — For adult vertebrates a large amount of 

 data is available upon various species for the loss in body weight during both 

 total and partial inanition. Chossat ('43) established 40 per cent as the usual 

 average of maximum loss in adult vertebrates, but recognized some exceptions 

 and variations, as are apparent in Table 1. The range is usually between 30 and 

 50 per cent. On the whole, however, there is in the various classes of vertebrates 

 comparatively little difference in the percentage of body weight which may be 

 lost in extreme inanition. The most important factor is the amount of stored 

 food reserves (especially fat). Many of the observed variations (for example, 

 sex differences) are probably due to this factor; although Ott ('24) finds a lesser 

 resistance in the female frog, in spite of the large ovarian mass available for 

 resorption (Table 6). Larger species or individuals will usually endure a greater 

 loss, while unfavorable environment (temperature, etc.) may produce death 

 with a smaller loss of body weight. Kahan ('85) observed that in pigeons the 

 daily average loss in weight increased with repeated intermittent fasts, but this 

 was not confirmed by Seeland ('88) in rabbits or by Stewart ('16) in albino rats. 



As to the course of the loss in body weight of animals during inanition, 

 Chossat ('43) concluded that in birds the loss is greatest in the first third of the 

 inanition period, least in the second third and intermediate in the last third. 

 Bourgeois ('70) comfirmed this for mammals. Moleschott ('59), however, found 

 that the final acceleration of loss is variable or absent. Lazareff ('95) for 60 

 guinea pigs on total inanition found a progressive decrease in the daily loss rate, 

 the average percentage loss for the eight successive days being roughly 9, 7, 6, 

 5, 4, 3, 3, 1.5. According to Rosenstern ('11) similar results were obtained by 

 Finkler (pigeons), Kuckein (chicks), Richet (ducks), Rubner (rabbits), Petten- 

 kofer, Luciani, and Laborde (dogs). For loss of body weight in various animals 

 during hibernation, see Polimanti ('05, '13), Valentin ('57); Rulot ('01). 



The data of Falck ('75) for dogs on total inanition may be taken as typical, 

 and the curves for two adults are shown in Fig. 31. Morgulis ('23) shows similar 

 curves for fasting dogs, based on Avrovov's data. 



