REPORT OF COMMISSIONER OF FISH AND FISHERIES. CXLIII 



distinct from regions occupied by certain copepoda and the still more 

 localized areas inhabited by ostracoda. 



FISH PATHOLOGY. 



Assistants of the division have made a number of examinations of 

 fishes that have died at various stations of the Commission, but usually 

 the results of the studies have been unsatisfactory. Lesions have 

 sometimes been found which would result in death, but the causes of 

 the morbid processes or conditions have not been apparent. In other 

 cases no clew to the disease has been detected. 



One of the most important subjects now connected with fish-culture 

 is fish pathology. With the exception of the effects produced by a few 

 animal and vegetable parasites, practically nothing is known of the 

 diseases of fishes. This is a very inviting field for study from the scien- 

 tific standpoint and from the practical standpoint of fish-culture. A 

 very large mortality not infrequently prevails among young and mature 

 fish at hatching stations, in stocked waters, and among wild fish, for 

 which there is no known cause or remedy. The annual unavoidable 

 losses in the Commission, while not excessive, are yet sufficiently serious 

 to demonstrate the necessity, which has long been appreciated, for an 

 assistant who could devote his whole time to the consideration of fish 

 diseases, and who is fitted by previous training in human pathology to 

 fully comprehend the nature, cause, and possible remedies for the now 

 obscure affections prevailing among the food aud game fishes. It is 

 strongly urged that the Commission be provided with a permanent 

 expert in fish pathology. 



WOODS HOLE, MASSACHUSETTS. 

 WORK IN THE LABORATORY. 



During the summer of 1897 the Woods Hole laboratory was occupied 

 by a small number of investigators, the Commission having restricted 

 the attendance to representatives of those institutions which had fur- 

 nished financial aid in the construction and equipment of the laboratory. 

 Among those at the station were Dr. John Y. Graham, of the University 

 of Alabama, and formerly of Princeton University; Mr. F. N. Balch, of 

 Harvard University ; Mr. Charles W. Greene, of Johns Hopkins Univer- 

 sity; Dr. J. Percy Moore, of the University of Pennsylvania, who was 

 engaged in studies on the embryology of the mackerel in the interest of 

 the Commission. At the request of the Smithsonian Institution, Prof. 

 C. C. Nutting, of the University of Iowa, was granted laboratory priv- 

 ileges to enable him to complete his work on American hydroids for 

 the institution. 



In the spring of 1898 it was determined to take steps to increase the 

 opportunities for scientific study at Woods Hole, by providing for the 

 prosecution of inquiries throughout the year instead of only during 

 the summer months, as heretofore. It was also decided to place the 

 laboratory in the charge of some competent biologist, who would be in 



