36 ANNALS NEW YORK ACADEMY OF SCIENCES 



prove fatal. Hyde ('08 ) estimated that the blood of the skate is equal 

 to one-twentieth of its body weight. Even if we assume that the total 

 quantity of blood of Mustehis is equal to five per cent of its body weight, 

 in none of the preceding experiments was one-half of the total blood of 

 the body taken. Table XIV shows the results of the experiments in 

 which the A's of the blood were obtained from different samples taken at 

 intervals from the caudal artery of fishes immersed in sea-water. 



In the above series of experiments, more blood was intentionally taken 

 for each determination of A than was used in the preceding cases. As 

 indicated above, the object of the experiments was to ascertain the effect 

 of bleeding on the osmotic pressure of the blood. There was no difficulty 

 in obtaining blood from any of the fishes experimented upon in the pres- 

 ent connection. All were alive and breathing regularly at the time the 

 last sample was obtained. The percentage of the total quantity of the 

 blood given in each case is only. a rough estimate based on the assumption 

 that the total quantity equals five per cent of the body weight. In esti- 

 mating this, the last sample was not included. In reviewing the results, 

 it is to be noted that there is a slight rise in the freezing point of the 

 blood of specimens 1, 2 and 5. The remaining six show a fall in the 

 freezing point. On referring to the accompanying data in each case, it is 

 found that the rise or fall in A is not related to the sex, length or weight 

 of the fishes, or to the amount of blood taken. In many of the cases after 

 the initial change, there is no further modification in A. It is possible 

 that these small variations from the normal A are indications of the nor- 

 mal fluctuations in the osmotic pressure as maintained on page 6. The 

 evidence presented in Table XIV is offered as further support for this 

 conclusion. Finally, attention is called to the fact that the maximum 

 changes are slight as compared with those recorded as due to the effects 

 of fresh water and concentrated sea-water. On the whole we are justi- 

 fied in concluding that the effects recorded in Tables VII and VIII 

 were due to the modifications in the molecular concentration of the ex- 

 ternal medium. Buglia ('08) found that simple bleeding produced in the 

 physico-chemical properties of dog's blood variations absolutely negligible 

 as compared with those obtained after injections of salt solutions hyper- 

 tonic to the blood. 



Additional Changes in the Blood Due to Alterations in the 

 Concentration of the External Medium 



changes in the erythrocytes 



One might conclude from the above changes in the osmotic pressure of 

 the blood of fishes exposed to fresh water that the corpuscles were laked 



