PHYSIOLOGICAL STUDIES OF THE CHINOOK SALMON. 



439 



Table V. — Sliowing the relation of Ou normal ventral aortic blood pressun tolength in ?4 specimens. The 

 hm is drawn through the mean or average. Th figures refer to th specimen numbers. 



/20r 



//O 



100 



90 



a 60 



a 



70 



60 



SO 



40 



SO 60 70 SO 90 



Length in centimeters. 



/OO 



/IO 



/20 



The mean blood pressure for the 13 females included in the table of relatively 

 normal Hsh is 75.4 millimeters of mercury. These salmon vary in length from 67.2 

 to 116 centimeters, and the blood pressures obtained from 50 to 120 millimeters of 

 mercury. The majority of these specimens were artificially spawned females, hence 

 a question may be raised as to how far these represent the normal or average condition 

 of the circulatory apparatus. The artificially spawned females that were used were 

 allowed to recuperate for several hours or even for a day or two after the eggs 

 were taken and before the blood pressure was measured. One would think that the 

 artificial spawning process would leave the fish more or less completely exhausted, 

 but this does not seem to be the case, barring the temporary asphyxia that comes 

 from keeping the specimens out of the water for the time required to spawn them. 

 When thrown back into the water these females become lively and vigorous in a very 

 short time. An illustration will suffice to explain the situation. A series of four 

 selected females from the ripe pen were artificially spawned on the morning of Aug. 

 28, 1901, then thrown back into a pen to recover for the experiments of blood 

 pressure. The afternoon of the same day these females, Nos. 52, 53, 54, and 55, 

 gave good strong pressures, as will be seen by a glance at the table below. One of 



