Biological Survey — Erie-Niagara Watershed 



147 



Table 3. — Normal Numbers of Erythrocytes to Yield 100 Per Cent 



Hemoglobin 



All these tables and all our experiments thus far have shown 

 one development for which we have no explanation. After the 

 first removal of blood from a fish, the level of hemoglobin and red 

 cell count sinks to about two-thirds the normal value. After this 

 the reduction rate seems considerably slower. It seems as if the 

 fish does not draw upon its reserves until after it has suffered a 

 reduction that is Avell below the normal. This illustrates the 

 unusual factor of safety a fish has for swimming through waters 

 of low oxygen content. This is an interesting contrast to our 

 experience with white rats who will practically exhaust their 

 reserves in an effort to maintain their initial level of hemoglobin 

 and red cells. 



In Table 5 we have assembled data for the specimen upon whose 

 blood the most studies have been carried out. Dr. Youngberg^ 

 studied the phosphorous distribution upon three different samples 

 of this blood. As a concluding experiment we determined the 

 blood volume by injecting a solution of Evans Vital Red directly 

 into the circulation in the ventricle of the heart. After allowing 

 the fish to swim for six minutes another blood sample was with- 

 drawn and the blood volume determined by the method of H. 

 Bakuin and H. Rivkin, employed upon babies.^ This yielded 

 a value which showed the blood volume to be eight per cent of 

 the body weight. While we consider this value too high, other 

 data indicate that it should lie somewhere between three and five 

 per cent of the total body weight. 



^ Dr. Guy Youngberg of the University of Buffalo School of Medicine renderep 

 important assistance by cooperating with Dr. McCay in these studies. 

 » Am. J. Dis. Children (1924) 27 p. 340. 



