246 ABSTRACTS OF MEMOIRS. 



Some Notes on Parasitic and Other Diseases of Fish. By 6. H. 



Drew. Parasitology, Vol. II, No. 3, September, 1909, p. 193 ; second 

 series, Vol. Ill, No. 1, April, 1910, p. 54. 



An examination of a number of diseased fish was undertaken primarily 

 with the object of finding cancerous growths. Many of the specimens 

 were obtained by the s.s. Huxley in the North Sea. 



Four cases of cancer were found resembling in appearance and 

 structure malignant cancerous growths in man. Two of these 

 originated in the pancreas of two specimens of plaice, and two in 

 the livers of rainbow trout. There seems no reason to suppose that 

 these growths are not in every way comparable to true carcinoma 

 as found in man. One case of a superficial growth in a dog-fish 

 was found, closely resembling the growths known as endotheliomata, 

 which are generally included in the term " cancer." A number of cases 

 of "benign" tumours were found {fibromata, myxo- fibromata, etc.), 

 chiefly in plaice and salmon, and these also showed the closest resem- 

 blance to similar tumours in human beings. It thus seems probable 

 that, whatever may be the cause of cancer and other tumours in man, 

 the same cause may be operative in the production of similar growths 

 in fish. 



Several cases of disease due to sporozoon parasites were investigated, 

 and two new species of sporozoa were described. 



A number of cases of an affection of the swim-bladders of trout, 

 resulting in the death of a large number of fish, were investigated. 

 It was found that nematode worms made their way from the intestine 

 into the swim-bladder by burrowing through the tissues, and carried 

 bacteria with them, which set up an acute septic inflammation. 



An outbreak of a contagious disease among fish in the Hertfordshire 

 Colne was also investigated, and it was recognized as a recrudescence 

 of the " salmon disease," in this case attacking fish of many different 

 species. The specific bacteria were isolated, and also the white fila- 

 mentous fungus, which grows freely on the lesions caused by the 

 bacteria, was identified. 



G. H. D. 



