7 
[41] BIOLOGY OF THE RHINE SALMON. AGT 
~ elearly shown by the circumstance that the muscles of the ventral fins, 
_ which most assuredly are not homologous with the muscles of the trunk, 
form an exception to the rule. The muscles of the ventral fins degen- 
erate in a moderate degree; and, though they show a marked decrease 
of albumen, it is by no means as striking as that of the muscles of the 
trunk. 
At first sight one would feel inclined to think of the nerves on which 
the condition of the muscles depends to a large degree. But in vain 
_have I sought for degenerated nervous fibers; and, moreover, how can 
it be possible that primitive bundles, some of which are greatly and 
others but little or not at all degenerated, should be found close to- 
gether, as—considering the very small number of nerve-fibers entering 
from the spinal marrow—large masses of muscle are supplied by 
branches of a primitive fiber? 
It therefore seems necessary to turn in another direction for the de- 
sired explanation. In soaking portions of different muscles of a salmon 
(which have been carefully weighed), such as those of the pectoral, ven- 
tral, dorsal, and anal fins, and those of the tail and the tongue, in equal 
quantities of water, we find—as the result of nnmberless experiments— 
that, without exception, the muscle of the trunk produces the extract 
having the least color of blood. Next to it comes the ventral fin, whilst 
the reddest extract, often possessing a threefold coloring power, is pro- 
ducedfrom the pectoral fin.* The same result is obtained with sea sal- 
mon, whose trunk muscle shows no signs of degeneration. It is the ex- 
pression of the varying wealth of blood-vessels, which is also noticed in 
preparing fish. 
As the fish in question is a starving fish, the blood cannot be con- 
sidered as a food-giving liquid, but can only come into play in as far 
as it is of importance for breathing. 
Here the accepted axioms of physiology leave us in the lurch. When- 
ever it was reported that the organs of a famishing animal decreased in 
varying degrees, these were principally supposed to be differences in 
the self-consumption of the organs. In view of this, the grand effort 
of the Rhine salmon—the building-up of its ovarium from the muscle 
of the trunk, will hardly be considered by any one as an isolated bio- 
logical curiosity. Essentially analogous occurrences probably take place 
a thousand times under circumstances which are far more difficult to 
understand. In my opinion the experience which we have gathered 
with regard to the Rhine salmon is destined to extend our knowledge 
of the dependence of the life of the cells on external causes, by adding 
another fundamental principle, in which, possibly, one of the most im- 
portant laws of nature as to the formation of portions of the animal body 
may lie concealed. 
There is a period in the life of the cells of active animal tissue in 
*The muscle of the skin cannot be considered in this connection, because its fibers 
contain the coloring matter of blood. 
