430 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 
the salmon have not eaten anything for some time prior to their ascend- 
ing the Rhine.* 
So far I have only found one exception to this rule. On the 3d of 
January, 1879, I received from an Jstein fisherman a male salmon which 
had been caught in the Rhine. It weighed 1.5 kilograms, had emitted 
all its milt, and was exceedingly lean. The transparent flesh had the 
smallest percentage of dry substance ever found by me in any fish—but 
13.56 per cent. In its flabby, wide stomach it had two tolerably large 
fish, to judge from their scales, Cyprinoids (probably Leuciscus), whose 
forepart had been digested. In another male salmon, which had emit- 
ted its milt, I found no remnants of food, but at least a somewhat 
extended stomach, containing a small quantity of a thin secretion pos- 
sessing acid reaction. In the majority of male fish, however, as well as 
in all the female fish of this stage, I found nothing of the kind. Neces- 
sity, which is the mother of invention, and which occasionally teaches 
the male salmon to eat, is probably not felt so much by the female 
salmon, because at the time when they begin their homeward journey 
to the sea (December tothe beginning of February), they find a substi- 
tute for food in the numerous eggs which have not been emitted, and 
which often number several hundred. 
I have been repeatedly assured that during the spawning months 
salmon are occasionally caught with the hook and line in the small 
streams such as the Wiese near Basel, whilst otherwise they will not bite. 
Although T have not been able to obtain positively trustworthy data 
with regard to this subject, I cannot, when thinking of my own experi- 
ence, deny it entirely—only, however, for the time after spawning. t 
Although it has been settled beyond a doubt that the Rhine salmon 
does not take any food whatever during the time it is ascending the river, 
including the spawning season, the facts which are given below compel 
me to maintain that at least in that portion of the Rhine which extends 
from Basel to Laufenburg all Rhine salmon are of one and the same kind, 
and that all of them, from the (supposed to be) barren winter salmon to the 
emaciated spawning salmon, represent stages of one and the same develop- 
ment, which—without an interruption—is completed in the Rhine. 
I base this opinion upon the following facts: 
(1.) There are in the different stages of development of the male and 
female sexual organs of our Rhine salmon no gaps which might justify 
the supposition that the barren winter salmon are replaced by com- 
paratively much maturer salmon ascending from the sea. DBarfurth 
has noticed this fact, but he has not followed it up to its last conse- 
quences. The instances given herewith in Table I show how the ovarium 
* According to my experienee, I must urgently advise to clean all sea salmon which 
are destined for a long journey, whilst with river salmon this is not necessary. . 
t According to Mr. Glaser it seems to be more certain that in the basin below the 
falls of the Rhine, near Schaffhausen nearly every year 1 to 4 salmon are caught with 
the hook and line, sometimes as early as October. 
