NINETEENTH ANNUAL REPORT 125 



quently affected were perches, flounders, alewives. smelts, hakes 

 and pickerels. 



Fishes that have died in captivity are frequently found on 

 autopsy to have a greatly distended gall bladder sometimes with 

 a general jaundiced condition due to the closure of the bile duct 

 either by inflammation or occasionally by parasites. 



A few cases of thyroid tumor have been found and fibrous 

 tumors have also been noted. Several cases of disease of the 

 jaws and other parts of the mouth, attended by the complete 

 destruction of the soft tissues laying the bony structures bare, 

 are obscure as to the cause and have not yet been thoroughly 

 studied. 



While such investigations made here and elsewhere may be 

 considered as only in the preliminary stage, enough has been 

 done to indicate that fishes sufi'er from many kinds of diseases 

 and to show also that the Aquarium is a fertile field for the study 

 of such diseases. It has been shown that while confinement is 

 conducive to the development and spread of certain parasites, in 

 other cases the parasites appear to be unable to withstand the 

 conditions of confinement as well as their hosts. It is unsafe 

 as yet to draw any conclusions as to the comparative frequency 

 of disease in fishes in the Aquarium and in outside waters. Para- 

 Bites and diseases are common in nature, but to what extent 

 they affect wild fishes is difficult to say, for the reason that when 

 such fishes are weakened by whatever cause they readily fall a 

 prey to their enemies and disappear. Under the protected con- 

 ditions of the Aquarium they remain for observation. 



In the early part of the year Dr. George G. Scott of the 

 College of the City of New York, was provided with laboratory 

 space and material for conducting his researches on the consti- 

 tution of the blood of fishes and on respiration and asphysia. 



The Whale Shark.— Prof. E. W. Gudger of the State Nor- 

 mal College at Greensboro, N. C, a collaborator of the U. S. 

 Bureau of Fisheries, and the Carnegie Institution of Washing- 

 ton, submitted an important paper on the Whale Shark. The 

 document was heartily recommended by the director, and was 

 accepted by the Executive Committee for publication, with illus- 

 trations, in Zoologica. 



A brief account of the whale shark was published in the 

 Zoological Societij Bulletin for November, 1913. This, the larg- 

 est of all fishes, exceeding fifty feet in length, is known to sci- 



