[BERKELEY] PENTOSE COMPOUNDS 45 



It is to be noted in the cases of the fishes that the organs which, 

 on general histological grounds, would be expected to be richest in 

 nuclei are not those which have the highest pentose content. The 

 testes, for instance, would be expected to consist almost entirely 

 of nuclear material and these are by no means the richest in pentose. 

 This is particularly noteworthy in the case of the Alaska cod and the 

 herring, which were spawning at the time the material was collected. 

 It is less marked in the cases of the two elasmobranchs examined, 

 but this might be connected with the fact that these fishes do not ripen 

 their sexual products all at one time and the testes were not ripe in 

 the same sense as those taken from the teleosts. Even in the case of 

 the elasmobranchs, however, the pentose content of the testis is 

 found considerably lower than that of the pancreas though it would 

 not be anticipated that the latter would be so highly nucleated. 



These expectations have been confined by comparing sections of 

 some of the tissues, stained to demonstrate the nuclei. '^ The sections 

 of the testes of the teleosts are found to be dense with nuclei whilst in 

 those of the elasmobranchs they are comparatively widely separated, 

 whilst the pancreas of the elasmobranchs is found to be considerably 

 poorer in nuclei than the testes. Another illustration of this point 

 is given by the separate pentose determinations in the soft tissue 

 and the connective tissue of the kidney of the dog-fish. The latter 

 yields very nearly as much as the former though it is very much less 

 densely nucleated. 



The pancreas could only be examined in the elasmobranchs. It 

 was found so diffused in the teleosts that it was practically impossible 

 to collect enough material for analysis. It is interesting to note that 

 in all three of these cases it is the organ containing most pentose. 

 This is in accordance with such observations as have previously been 

 made on mammalian organs. So uniformly has this been found to be 

 the case that it would seem to be justifiable to look for some connection 

 between the pentose nucleotides and the physiological function of the 

 pancreas. 



From the standpoint of comparative bio-chemistry the most 

 interesting thing about the results obtained from the fishes seems to 

 be the generally higher pentose content of the organs of the teleosts 

 than those of the elasmobranchs except in the case of the testes, of 

 which an explanation has already been suggested. More work is 

 required, however, before it can be concluded that this is invariably 

 the case. 



^I am much indebted to Mr. H. Dunlop, of the University of British Columbia, 

 for preparing and mounting these sections. 



