450 BULLETIN OF THE BUREAU OF FISHERIES. 



on blood and on serum from the same individual, then the mean depression produced 

 liv the serum is only 1.7 per cent below that of whole blood. This difference appears 

 almost wholly in two observations, Nos. 27 and 209, where the difference is 

 considerable. The presence of the corpuscles in suspension in the serum in whole 

 blood ought not to change the depression of the freezing- point unless the corpuscles 

 are disintegrating. Observations of Hamburger", Roth'', Bugarsky and Tangl', and 

 Stewart'' all indicate that the corpuscles are inert in freezing determinations and 

 nonconductors in electrical conductivity determinations. Considering the fact that 

 the serum has essentially the same concentration as blood, then No. 206, with a 

 serum that depresses the freezing point, —0.51.8 C, is the most dilute blood exam- 

 ined. This specimen was an old male off the retaining rack and in my list represents 

 the specimen nearest death and disintegration. The sides of this specimen were 

 covered with fungus patches, and the skin was broken on an area over the back and 

 on the nose. These pathological conditions would tend to bi-eak down the general 

 osmotic resistance of the skin, just as erosion of the skin permits free absorption of 

 materials in man or the higher animals. On the other hand, one must not draw the 

 conclusion that this is the only or even the primary factor leading to the dilution of 

 salmon blood in fresh water. In specimen 212 the skin was clean and perfect, and 

 the fish seemed externally in perfect condition as far as abrasions and general 

 appearance of the skin indicate. Yet the blood gave only — U.557 w C. and the ovarian 

 fluid the remarkably low figure of —0.429° O, some 0. 12 : below the general average 

 of the series. The lower the vitality of the tissues for whatever cause the more 

 dilute the blood was found to be. 



If salmon blood be allowed to stand for a day in a warm room, then the corpuscles 

 break up in large quantities and the increased number of ions and molecules set free 

 will of course increase the depression of the freezing point. Experiments in which 

 there was evidence of such change were discarded and do not appear in the above 

 considerations, as stated before. On the whole, the variations in the above table are 

 to be explained as due to the different condition of the individuals studied, differences 

 due to different times of sojourn in fresh water, differences in sex, vitality, etc. 



The difference in the blood of males and of females is especially noticeable. The 

 average depression for the whole blood of males is — 0.668 O, and for serum 

 —0.653°. The average for females is -0.610 c and — 0.605 : C. for blood and for 

 serum, respectively. This variation in the sexes amounts to about 8| per cent — i. e., 

 the female blood, as determined above, is 8f per cent less concentrated than male 

 blood and the serum 7£ per cent less. I believe this observation has its explanation 

 in the more profound changes taking place in the development of the large mass of 

 the ovary as compared with the relatively smaller mass of the testes, and in connec- 

 tion with the production of the large quantity of ovarian fluid at the time of the 

 ripening of the eggs. 



"Hamburger, H. J., Ueber die Regelung der osmotisehen Spannkraft von Fliissigkeiten in Bauch- und Peritoneal- 

 noble. Arcbiv f. Anat. u. Physiologie, Physiol. Abt., 1895, S. 281. 



''Roth. Win., Electrische Leitfiihigkeit thierischer Fliissigkeiten. Virchow's Archiv, Bd. 154, 1899, S. 466. 



'•Bugarsky and Tangl, Untersuehungen tiber die molecularen Concentrations- Verbaltnisse des Blutserums. Cen- 

 tral!), f. Physiologie, Bd. XI, 1897, S. 301. 



dStewart, G. N'., Elektriscbe Leitfiihigkeit thierischer Fliissigkeiten. Centralb. f. Physiologie. Bd. XI, 1897, S. 382. 



