352 LECTURE XVI. 



Direct observation confirms this. Microscopic examination of the ovaries 

 and of the testes shows that most active processes of growth and trans- 

 formation are taking place. On the other hand, the large dorsal muscle 

 exhibits all the signs of a far-reaching release of its stored material 

 and of even the contents of its cells, the muscular fibers. Everything is 

 not given up, but as much of the material as can be spared is transformed, 

 leaving enough behind so that subsequently when the salmon returns to 

 the sea the muscles may be regenerated. It is the large dorsal muscle 

 which entirely provides the material for the changes taking place in the 

 body of the starving fish, whereas the remaining muscles undergo no 

 change that indicates in any way a migration of material. It has never 

 been satisfactorily explained just how this migration takes place. Miescher 

 describes the appearance of small drops of fat between the muscle fibrils. 

 The amount of these drops may become so great that the whole muscular 

 fiber becomes opaque. It is obvious that in this way preparation is 

 being made for a migration of fat. Besides albumin and fat, the muscle 

 must give up phosphates which in the formation of eggs evidently become 

 a part of the lecithin. The other salts and substances, such as choles- 

 terol and the nuclein substances required to form the nuclei of the eggs, 

 must likewise be obtained from the dorsal muscle. It is evident, there- 

 fore, that the migration of substance here attains large dimensions. 

 Undoubtedly a study of this interesting biological phenomenon by modern 

 methods would give us considerable insight into the extent of the syntheses 

 capable of being carried out in the organism. Every supply from the 

 outside is cut off. The entire sexual products are formed from material 

 taken from the dorsal muscle. It is clear that a comparison of the amount 

 of lecithin, nucleic acids, etc., contained in this muscle with those of the 

 sexual products, would give us a good idea of the metabolism and of the 

 chemical processes involved. 



These observations permit us to draw certain conclusions concerning 

 metabolism during starvation. 1 If every source of food supply is cut off 

 from an animal, then the organism turns to its own body for nourishment. 

 Carbon dioxide is constantly being eliminated and oxygen absorbed, and 

 likewise the chemical composition of the urine gives unmistakable proof 

 that combustion is continually taking place, which in warm-blooded 

 animals suffices not only for the performance of mechanical work, but also 

 for maintaining the temperature of the body. If we compare the relative 

 proportions by weight of the separate organs of a starving animal with 

 those of one that is well nourished, it is at once apparent that the different 

 organs do not participate equally in the metabolism. Thus the nervous 

 system and the heart show but slight, if any, changes in their composition 



1 S. M. Lukjanow: Z. physiol. Chem. 13, 339 (1889). C. Voit: Z. Biol. 31, 510 (1894). 

 A. Hermann: Pfluger's Arch. 43, 239 (1888). 



