472 REPORT OF COMMISSIONER OF FISH AND FISHERIES. ([46} 
convalescent muscle of the trunk. To all appearances hunger, in its 
most threatening aspect, does not make itself felt till this time, and com- 
pels the fish to enter upon its return trip. These late travelers, on their 
return to the sea, often show little knots in the spleen again, sometimes 
even considerable swellings. We know now what this means; some 
organic albumen has to be “liquidated.” 
Mr. Glaser is inclined to consider the period of this return journey 
as very short (shorter than I have estimated it), because these fish, in 
their haste, dash against the sand-banks near Ste in, and there run 
aground, which at other times does not occur. We must also remem- 
ber that nearly the same weight of fin-muscles has to move a much 
smaller mass of body, and, what is also in its favor, down the stream. 
As regards the male fish, the spleen, owing to their greater self-con- 
sumption, seems to be drawn upon as early as May and June, when not 
much weight can be attached to the increase of the testicles. During 
the summer, and up to September, there are many changes; we some- 
times find small, and at other times average-sized spleen, with various. 
intermediate sizes, as it seems to me, in some way corresponding to 
the varying quantity of blood in the sexual glands; but my investi- 
gations of this matter are not far enough advanced to lay down any cer- 
tain rule regarding it. It seems somewhat singular, especially when we 
compare with it the striking regularity of this change from small to 
large spleen in the female fish; which regularity remains the same, no 
matter whether some of the female fish are more belated than others. 
Could varying conditions of sexual excitement have an influence on 
the consumption of matter? One thing, however, is certain: in Octo- 
ber, generally early in the month, we find as a rule large (and the largest) 
spleen. All the maximum weights (as high as 0.86 per cent. of the 
weight of the body, or sixteen times the smallest weight observed in 
males) belong to this period. During the spawning period the weight 
of the spleen again decreases gradually. 
The maturing of the sexual gland of the male fish does not require as 
large quantities of albumen and fat as the ovaruim of the females, but 
as far as my experience goes,* the sexual gland needs all the more 
phosphoric acid salts to form the various substances of the semen which 
contain phosphorus. Taking the weight of the mature testicles as 5 per 
cent. of the weight of the body, with 25 per cent. dry substance of 11.3 
per cent. phosphoric acid,t we find that the growing testicles must take 
away from the blood 0.141 per cent. phosphoric acid; a larger quantity 
than is contained in one-half of the mature ovarium of a female fish of 
equal size. Why should not the hunger for phosphorus with the male 
fish produce similar effects as the hunger for albumen with the female? 
* Die spermatozoen einiger Wirbelthiere (The spermatozoa of some vertebrates), in the 
Transactions of the Pasel Society of Natural History, vol. vi, part 1, p. 147. 
tThe same work. 
