THE GERMAN CARP IN THE UNITED STATES. 567 
macroscopically were rarely seen. In a few cases fragments of the 
higher water plants (e. g., Aanunculus) were found in the esophagus, 
while from the eolor of the small amount of fluid contents it was 
believed that green algze might have been eaten. In the Maumee 
River the carp fed constantly and largely upon whole wheat that had 
been lost in the river a season or two previous in a grain elevator fire. 
From the foregoing it appears that a large proportion of the mate- 
rial found by dissection in the alimentary tracts of carp was of vege- 
table origin. Since this material is eaten in such quantities and is 
digested in its course through the fish, as is shown by observation, the 
natural supposition is that it serves as food. And such is the opinion 
of most writers onthe subject. Nicklas (1884), however, who discusses 
at much length the question of the proper food for the ‘‘artificial 
feeding ” of earp, arrives at a different conclusion. It is his theory 
that these fish should be fed on materials especially rich in nitrogen- 
ous compounds, and in this connection he says (pp. 1011, 1012): 
I have started my theory from the fact, which I know from actual experience, that 
the food of the carp is principally animal and not vegetable matter, and I find that 
in this I agree with most of the practical pisciculturists; but I differ from the views 
of Professor Nawratil (Oesterreichisch-Ungarische Fischerei-Zeitung, 1880, No. 35) 
when he asserts that carp, from their third year, live principally on fresh and decay- 
ing vegetable matter. This is contradicted by the experience that they are easily 
raised in ponds which contain but few plants, and by the circumstance that, if aquatic 
plants formed the exclusive, or even principal food of carp, vegetation would, in some 
ponds, be utterly destroyed in a few days after they had been stocked with carp, or 
at any rate in a couple of years, as carp are particularly fond of young shoots, which, 
by the way, show a pretty close proportion of nutritive matter [to animal food?]. 
Such an occurrence, however, I have never yet been able to observe, nor has it been 
observed by any other pond-culturist; whilst, on the other hand, it has frequently 
been observed that in carp-ponds vegetation becomes so rank and luxuriant that it 
has to be checked. As long as decaying vegetable matter has not been examined as 
to the quantity of nutritive substances contained in it, no opinion can be formed as 
to its suitableness for carp food. 
My own observations have taught that the carp only takes to vegetable food when 
absolutely no animal food can be procured. I have not yet been able to ascertain 
whether the carp actually eats and digests decaying vegetable matter, because all I 
have so far been able to observe has been that the carp often swallows such matter, 
but almost immediately ejects it again, perhaps after having devoured worms and 
insects clinging te such matter. 
I can not help feeling that Nicklas’s judgment is influenced by his 
theory. Although he may possibly be right as to the kind of food 
that will be most economical in putting a given amount of flesh on a 
carp in a given time, it nevertheless seems evident, as a matter of fact, 
that carp do under natural conditions eat a large quantity of vegetable 
feod. Ii Nicklas had examined the contents of the stomachs and 
intestines of the fish he observed, he might not have concluded that 
they ejected even ali of the decaying vegetable matter that they ate. 
While it is not probable that the actually decaying vegetable matter 
