THE GEEMAN CAEP IN THE UNITED STATES. 567 



macroscopically wore rarely seen. In a few cases fragments of the 

 higher water plants (e. g., Rammculus) were found in the esophagus, 

 while from the color of the small amount of fluid contents it was 

 believed that green alga? 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 on the subject. Nicklas (1884), however, who discusses 

 at much length the question of the proper food for the "artificial 

 feeding" of carp, 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 pisdcuJijuriste; but I differ from the viewa 

 of Professor Xawratil (Oesterreichisch-tTngarische Fischerei-Zeitung, L880, 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 . 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; Avhilst, 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 aide to observe has been that the carp often swallows such matter, 

 but almost immediately ejects it agaiu, perhaps after having devoured worms and 

 insects clinging to 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 

 food. If Nicklas had examined the contents of the stomachs and 

 intestines of the fish he observed, he might not have concluded that 

 they ejected even all of the decaying vegetable matter that they ate. 

 While it is not probable that the actually decaying vegetable matter 



