PHYSIOLOGICAL STUDIES OF THE CHINOOK SALMON. 453 



I have seen such females opened, but n<> liquid was present. Males do not con- 

 tain more than a few drops of abdominal cavity liquid. In one of the largest male 

 specimens used not enough liquid could he obtained from the body cavity for a freez- 

 ing determination. 



The ovarian liquid is a clear, limpid, slightly translucent fluid very like mamma- 

 lian transudates, hydrocoele fluid for example, in appearance. It makes its appear- 

 ance when the eggs are being set free from the ovary and following this event. 

 Paton" gives a quotation from Miescher-Reuseh containing the phrase "the ovarian 

 fluid which readily exudes from the ripe ovary when broken down." Miescher- 

 Ruesch'' says that this ovarian fluid is a rich concentrated liquid to be regarded 

 chemically as a '"liquid caviar." lie says that the fluid gives the proteid reactions, 

 that it is rich in phosphorized fat (lecithin), containing as much as 20 per cent, and 

 that on digestion with artificial gastric juice it gives a further yield of phosphorus 

 derived from nucleo-proteid. The ovarian fluid in the chinook salmon is much more 

 fluid and less concentrated than in Sahno solar, if one can rely on the observations 

 referred to above. 



At the time when the eggs are set free in the body cavity there is a very pro- 

 found rupture of the surface of the ovary. There are from 4,000 to 6,000 and even 

 more eggs in each ripe female, hence it is obvious that the entire surface of the ovary 

 is involved in this morphological disturbance. So large a ruptured surface would 

 furnish an ideal condition for the transudation of materials from the blood and the 

 tissues. It is probable also that some of the liquid comes from liquefaction processes 

 in the ovary itself antecedent to and resulting in the freeing of the eggs, though the 

 quantitative relations do not justify the assumption that this latter source accounts 

 for more than a fractional part of the total liquid. Hedin' calls attention to the close 

 correspondence in osmotic tension of blood and transudates, a relation which does not 

 exist between the blood and secretions, a correspondence close enough in this instance 

 to class the ovarian fluid as a transudate. I have not seen indications of the presence 

 of blood pigment in the ovarian liquid which would indicate rupture of blood vessels 

 in the ovary. True, the blood is sometimes present in the artificially spawned mass 

 of eggs and fluid, but always under conditions that point to artificial rupture of ves- 

 sels (usually in the spleen) by the mechanical pressure of spawning. Occasionally 

 the ovarian fluid has a slight yellow color the same as that of the eggs. This color is 

 attributed to the rupture and disintegration of eggs in the body cavity itself. 



COMPARISON OF THE FREEZING POINTS OF BLOOD OF SALMON FROM THE DIFFERENT 



REGIONS. 



The average depression of the freezing point of the salmon blood is, for sea 

 salmon, — 0.762 c C; for brackish-water salmon, —0.737° C, and for spawning-ground 

 salmon, — 0.628 c C. The decrease in concentration for the second and third groups, 

 compared with the first as a standard, is represented by —0.025° C. and —0.134° C. 



a Paton, D. Noel, Report of the Fishery Board for Scotland, 1898, p. 143. 



&Mlescher-Rueseh, F. st:itisti*rht.' nn.1 lii. .l.^i-.-lh I-:.-ii i i;i^o zur Kemitniss vum leben des Rheinlachses im Siiss- 

 wasser. Schweizerischer Fischerei-Ausstellung zu Berlin, 1880, 154. 

 c Hedin, S. G„ Skand. Archiv f. Physiologie, 5, s. 277. 



