approximation of a correction factor for 

 data obtained by dissection. The correction 

 factor was added to each of the individual 

 dissection counts presented in table 1, and 

 an analysis of the corrected dissection 

 data and the digestion data in table 1 W£is 

 carried out This analysis (table 3) demon- 

 strated that a significant difference did 

 not exist (t = 0.50, N = 39, not signifi- 

 cant at P = 0.50) which indicated that the 

 significant difference obtained with the 

 uncorrected data in table 1 was due to the 

 difference in efficiency of recovery of 

 the worms by the two methods rather than 

 to differences in the distribution of the 

 worms between the two sides of the fish. 



It should be realized that the cor- 

 rection factor used in this analysis was 

 merely a first approximation. A true cor- 

 rection factor probably would be a function 

 of the number determined by the dissection 

 procedure. The determination of an accurate 

 factor would require more data than obtained 

 in the present study. 



Preliminary observations indicated 

 that the population of Anisakis sp. larvae 

 was concentrated in the musculature of the 

 ventral section of the fish. Thirty fil- 

 lets of chum salmon, each obtained from the 

 right side of a fish, were divided along 



Table 3. — Correction of Anisakis sp. count of table 1 using 



the lateral lines into dorsal and ventral 

 sections. The sections were digested sepa- 

 rately, and the number of worms in each of 

 the sections was determined. The data, 

 which are presented in table 4, demonstrate 

 the preponderance of worms in the hypaxial 

 musculature. 



Discussion 



The application of enzymatic prote- 

 olysis to the recovery of tissue-bound 

 parasites has found considerable use in 

 parasitology (Gustavson, 1953; Hoffman, 

 1955; among others). The successful use 

 of enzymatic digestion in the Ccise of nema- 

 todes undoubtedly depends upon the resist- 

 ance of the cuticle to the proteolytic 

 attack of the specific enzyme used. The 

 resistajice is due to the collagenous nature 

 of the cuticle as demonstrated by Chitwood 

 (1936) and more recently by Bird (1957). 



In all cases of which the authors are 

 aware, the enzymatic digestion techniques 

 have been pointed toward recovery of living 

 parasites for subsequent use in morphologi- 

 cal, physiological, or infectivity studies. 

 Under these conditions, enzymatic digestion 

 of the investing tissue must be carefully 

 controlled, lest the physical conditions of 

 the system, notably temperature and hydrogen- 

 ion concentrations, exceed the tolerance 

 of the parasite in question. The enzymes 

 pepsin and trypsin, for exjimple, most 



Table 4. — Anisakis sp. count by digestion method on dorsal 



Sample Total Dorsal Ventral 

 No. count count count 



