September 4, 1885. 



SCIENCE. 



197 



MOSQUITOES VS. TROUT. 



Mk. C. H. Mukeay of Denver writes to Professor 

 Baird the following letter, whicli we are permitted to 

 print in advance of its publication by the U. S. fish 

 commission : — 



In the middle or latter part of June, — I think it 

 was, — in 1882, I was prospecting on the head-waters 

 of the Tumiche Creek in the Grunnison valley, Col. 

 About nine o'clock in the morning, I sat down in the 

 shade of some willows that skirted a clear but shal- 

 low place in the creek. In a quiet part of the water, 

 where their movements were readily discernible, 

 were some fresh-hatched brook or mountain trout; 

 and circling about over the water was a small swarm 

 of mosquitoes. The trout were very young, still 

 having the pellucid sack puflBng out from the region 

 of the gills, with the rest of their body almost trans- 

 parent when they would swim into a portion of the 

 water that was lighted up by direct sunshine. Every 

 few minutes these baby trout — for what purpose I 

 do not know, unless to get the benefit of more air 

 — would come to the surface of the water, so that 

 the top of their head was level with the surface of 

 the water. When this was the case, a mosquito 

 would alight, and immediately transfix the trout by 

 inserting his proboscis, or bill, into the brain of 

 the fish, which seemed incapable of escaping. The 

 mosquito would hold his victim steady until he had 

 extracted all the life juices; and when this was 

 accomplished, and he flew away, the dead trout 

 would turn over on his back, and float down the 

 stream. I was so interested in this before unheard 

 of destruction of fish, that I watched the depreda- 

 tions of these mosquitoes for more than half an 

 hour; and in that time over twenty trout were 

 sucked dry, and their lifeless shells sent floating away 

 with the current. It was the only occasion that I 

 was ever witness to the fact, and I have been unable 

 by inquiry to ascertain if others have observed a 

 similar destruction of fish. I am sure the fish were 

 trout, as the locality was quite near snow line, and 

 tlie water very cold, and no other fish were in the 

 stream at that altitude. From this observation, I am 

 satisfied that great numbers of trout, and perhaps 

 infant fish of other varieties in clear waters, must 

 come to their death in this way; and, if the fact has 

 not been heretofore recorded, it is important to those 

 interested in pisciculture. 



LAST YEAR'S MEETING OF THE 

 AMERICAN ASSOCIATION. 



The proceedings of the American associa- 

 tion for the advancement of science for 1884 

 were ready for publication only just prior to 

 the date appointed for the meeting at Ann 

 Arbor. They extend through 736 pages, to 

 which there is an index covering sixteen 

 pages. As usual, a large part of the papers 

 are represented only by titles and abstracts, 



some others have already been printed ; so that 

 the volume is chiefly to be valued for reference, 

 rather than for the freshness of its contents. 

 It appears to have been carefully edited by 

 the secretary, and to contain in exact and con- 

 venient forms all the general information re- 

 specting officers, membership, committees, and 

 official acts to which we have been so long 

 accustomed. Of course we cannot allude 

 specifically to the long arra}^ of scientific com- 

 munications here presented ; but we will ven- 

 ture to call the attention of the general reader 

 to the A^arious addresses which he will find in 

 the volume, and which, taken collectively, afford 

 aver}^ good insight into the aspect of scientific 

 studies in this countr}^ and at this time. 



A re-examination of the opening address of 

 Prof. C. A. Young of Princeton, on the ' Pend- 

 ing problems in astronomy,' has confirmed our 

 first impressions of its value. Indeed, we do 

 not hesitate to call it a model discourse for 

 such an occasion. The president of the as- 

 sociation selected a theme which he w^as full}' 

 qualified to discuss, — one which enabled him 

 to look forward as well as backward, one 

 which was of equal interest to the astronomer 

 and to the students of other sciences. The 

 style in which he wrote was bright, and fitted 

 to engage the attention of any well-educated 

 person, while it remained free from all that was 

 extraneous or sensational. No better intro- 

 duction can be found to the present condition 

 of astronomical science. 



The addresses of the vice-presidents are also 

 given. That of Professor Eddy is a complaint 

 and an appeal, with respect to the neglect of 

 mathematics by our countrymen, and recalls 

 a like complaint which was made by Professor 

 Newton when he was sectional vice-president 

 a few years ago, and a well-known article b}' 

 Professor Newcomb in the North- American 

 review for 1874. It is difficult to account for 

 the intellectual abstinence of Americans, to 

 which these writers refer, from domains so in- 

 exhaustible as those of modern mathematics, 

 except by remembering the eagerness of every- 

 body in this land — scholars and teachers, as 

 well as investors and merchants — for imme- 

 diate results, — for the concrete rather than 

 the abstract. Professor John Trowbridge enti- 

 tles his address ' What is electricit}' ? ' — a ques- 

 tion which he knows, as well as anybody, is 

 easier asked than answered. Nevertheless, 

 around this inquiry he has grouped a large 

 number of important and suggestive state- 

 ments, which were particularly appropriate at 

 a time when the national electrical congress 

 was about to meet in the city of Franklin. In 



