TEE BREEDING SALMON. 51 1 



and clearness. The constituents of the genitalia are essentially different 

 chemical compounds from the suhstances of the muscles out of which 

 they are manufactured; yet the fact that their formation takes place 

 wholly during the period of the animals' fast, leaves no other source 

 for them. In the synthesis of these complex organic substances, the 

 j.ihosphorus — to mention only one element — can be traced with cer- 

 tainty back to the simple phosphates stored in the muscles of the 

 salmon of the estuaries. 



The mechanism by which this material is transported and trans- 

 formed was the subject of much careful investigation by Miescher. 

 lie noted a marked increase in the functional activity of the spleen — 

 an organ as enigmatic in the salmon as in man. He observed also a 

 decrease in the blood supply to those muscles at the expense of which 

 the genitalia grow, and an equal increase to the genitalia themselves. 

 The special significance of these conditions lies in the fact that a very 

 small blood supply, continued through the summer and autumn, would 

 transport many times the amount of material which actually becomes 

 a part of the genitalia. As these organs are not motile, and are appar- 

 ently the seat of no marked oxidation, their respiratory needs would 

 appear small. Nature, however, follows closely the principle of 'least 

 action'; and Miescher advanced the theory that, aside from its part 

 in respiration, the oxygen brought to the tissues by the blood exercises 

 a tonic influence upon their constructive processes. Thus in the liquefy- 

 ing muscle the lack of oxygen causes a stoppage and reversal of nutri- 

 tion. The cell contents are absorbed into the blood. In the genitalia 

 on the other hand the excess of oxygen in which the cells are bathed 

 stimulates their nutritional processes, and results in vigorous growth. 

 This view is, of course, a pure hypothesis. Yet it is interesting on 

 account of its close similarity to theories advanced now, a generation 

 later, by pathologists to explain the causes of abnormal growths in 

 the tissues of man. 



Important as are the results of the study of the salmon thus far 

 mentioned, none rank in value with Miescher's investigations on the 

 chemical nature of the sperm and ova. These researches were prac- 

 tically the first in which there was an attempt to lay bare the chemical 

 processes involved in fertilization and the formation of the embryo. 

 The clue which Miescher furnished has been followed by others, until 

 to-day we seem to be approaching a determination of the structure of 

 the proteid molecule — the first step necessary to solving the problem 

 of the chemistry of living matter. Modern histology has shown that 

 the fertilization of the ovum, from which the animal body develops, 

 consists essentially in the entrance of the nucleus of the spermatozoon 

 or male cell, and its fusion with the nucleus of the ovum. The nucleus 

 of the spermatozoon must therefore be regarded as the carrier poten- 



