672 



PHYSIOLOGY 



terises the state of inanition. During the starvation all tissues of the body 

 undergo a process of slow autolysis or disintegration, giving up the products 

 of this process to the common circulating fluid. The nutritional demands 

 of a tissue are determined by its activity. Hence the active. tissues of the 

 body take up the material set free from all the other cells of .the body and 

 so maintain their weight at the expense of all other parts. A similar pre- 

 dominance of the nutrition of active over inactive tissues is to be observed 

 in cases of partial starvation, i. e. where the deprivation of food applies only 

 to a single food constituent. Thus Voit, in a series of experiments, fed 

 pigeons on a food which, while normal in all other respects, contained a 

 deficiency of calcium salts. On killing the birds after a certain length of 

 time, it was found that while the bones used in the necessary movements 

 of the animals presented a normal appearance, the others, such as the 

 sternum and skull, showed a marked deficiency of lime salts and had under- 

 gone a process of rarefaction giving rise to the condition known by patho- 

 logists as osteoporosis. Many other instances of the sacrifice of a temporarily 

 useless tissue on behalf of tissue of high physiological value are known. 

 Thus the salmon and its congeners, which live part of the year in the sea, 

 lay their eggs and undergo their early development in the fresh water of the 

 upper reaches of rapid streams. An adult salmon leaves the sea in the early 

 summer months in a magnificent state of muscular development, fit to 

 perform the prodigious feats of swimming which are required in order to 

 get it over the rapids of the river which it has to ascend. It takes no food. 

 In the upper reaches of the stream or river there is a growth of 'the genital 

 glands, ovaries, or testes. The whole material for the growth of these large 

 organs is derived from the atrophy of the skeletal muscles. In this case 

 we have the growth of an active tissue at the cost of an inactive one, the 

 activity however being determined; not by the direct call upon it from 

 the environment, but by what we may speak of as the ' physiological 

 habit ' of the animal. 



The animal organism, in the complete absence of food, deals with the 

 resources of its bodily tissues with the utmost possible economy. The total 

 metabolism therefore sinks rapidly during the first two days of starvation, 

 and then remains practically constant. There is indeed a slight continuous 

 diminution with the fall in body weight, but the total metabolism per kilo 

 body weight till within a day or two before death is a constant quantity. 

 This is shown in the following Table of the output of energy in man during 

 a five days' period of starvation (Tigerstedt) : 



METABOLISM DUBING STARVATION 



