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Cancer Research 



* la tU* mmI like •ttccccding tables, the number <A tumor-bearing animals, when in eicess of one, follows the name of the spedes. 



inclusions which were surrounded by an achromatic 

 halo, and could be readily distinguished from nu- 

 cleoli. In what appeared to be their earlier stages 

 they were dense and compact; later they became 

 fluffy and less distinct. The author compared them 

 with the inclusions of vaccinia and other virus di- 



In 37 specimens of the stint Osmerus eperlanus 

 Breslauer (16) found tumors that likewise occurred 

 mainly on the lips, less commonly on the mucosa of 

 the oral cavity or on the fins. The fish were taken 

 from the brackish water of an inlet of the Baltic sea. 

 Upper and lower lips were affected equally; fre- 

 quently the tumors were in apposition. Some were 

 cauliflower-like growths, others were flat, varying 

 in size from small nodules to masses as large as the 

 head of the affected fish. Histologically all had a 

 papiUomatous structure. Usually they showed no 

 tendency to invade, but occasionally the arrange- 

 ment of the oeUs suggested early malignancy. Cyto- 

 plasmic induskms were sometimes, but not regular- 

 ly, encountered. 



It may be pertinent here to discuss the tumors re- 

 ported by Schroeders (179) and by Anitschkov and 

 Pavlovsky (3) in several sp>ecies of gudgeon Gobio, 

 a small marine flsh. The descriptions of the latter 

 authors particularly exemplify the difficulty of classi- 

 fying colain dun tumors of fishes; 3 tumors which 

 they regarded as distinct types may represent merely 

 different stages of the same neoplastic process. In 

 their first case there were numerous snoall nodules 

 and flattened elevations, the larger and more fully 

 devdoped ones distinctly papillomatous, with their 

 bates and the subjacent corium the site of a pro- 

 nounced inflammatory reaction; the authors likened 

 these growths to the chronic inflammatory papillary 



hyperplasia of the skin and mucous membranes in 

 man. In the second case a large rather flat solitary 

 growth was found on the dorsum of the fish, Gobio 

 nigronatatus. Histologically this had the character 

 of a benign papilloma and was not associated with 

 an inflammatory process. In the third case a rela- 

 tively massive, broadly sessile, cauliflower-like tu- 

 mor, 2x1x1 cm., occupied the dorsum of a small 

 Gobio blenniodes. It differed from the growth of the 

 second case in the markedly irregular hyperplasia 

 of its epithelial covering and in the delicacy of the 

 supporting connective tissue trabeculae. The tumor 

 did not infiltrate the subjacent tissues, and although 

 the authors regarded it as a papillary carcinoma, the 

 evidence for malignancy is inconclusive. The tumors 

 reported by Schroeders (179) are in the same genus 

 of fish, Gobio, and have the character of benij^n 

 papillomas. In the absence of information regarding 

 the further development and fate of these timiors, it 

 is impossible to be certain of their true nature. 



Mention must here be made of a non- neoplastic 

 disease of fish, which has sometimes been confused 

 with true tumor, the so-called pox-disease. It is par- 

 ticularly common in carp and may attain epidemic 

 proportions. The disease has no relation to the 

 various kinds of pox of man. Numerous milk-while, 

 flattened elevations are present on the epidermis of 

 the affected fish; so that it apfsears as if splashed 

 with melted paraffin which has solidified. All i>arts 

 of the body, including eyes and fins, may be af- 

 fected. Microscopically the lesions present a simple 

 hyperplasia of the epiderm; the corium usually re- 

 mains unchanged and sends no papillae into the 

 epithelial mass; however, a papillary structure is 

 occasionally attained by the larger and more per- 

 sistent growths. On hbtologic grounds no sharp dis- 



