34 ANNALS NEW YORK ACADEMY OF SCIENCES 



Effect of Loss of Blood on the Osmotic Pressure of the Blood 



OF Mustelus canis 



In the previous experiments, it will be noted that varying quantities 

 of blood were taken for the determination of the freezing point. About 

 five cubic centimeters were used for each determination, and as much as 

 six times that quantity was taken from many of the specimens. The 

 criticism might be brought that the loss of so much blood might have 

 introduced a serious modification in the results, so that what we were 

 attributing to the difl:erence between the molecular concentration of the 

 blood and the surrounding medium might in large part be due to loss 

 of blood. It was necessary therefore to make a control experiment in 

 which the conditions should be the same as those described on page 13, 

 with the exception that the fishes should be immersed in sea-water during 

 the entire period. 



Fano and Bottazzi (^96) observed changes in the osmotic pressure of 

 the blood of dogs associated with anemia produced by successive bleed- 

 ings. They noted that the osmotic pressure of the blood fell immediately 

 after the bleeding. They explained this as being due to a temporary 

 lowering of the blood pressure, which causes a diminution in the elimi- 

 nation of salts ordinarily released in secretions. As a result, those pro- 

 cesses which are concerned in the formation of lymph are depressed. 

 The authors suggested that the rise in the osmotic pressure may be due 

 to the abundance with which globulins are turned into the blood stream. 

 Globulins passing from the tissues into a less concentrated serum disso- 

 ciate themselves and separate from the bases with which they are com- 

 bined and contribute these to increasing the concentration of the blood. 



The work of these investigators is hardly applicable here, for the rea- 

 son that they experimented upon dogs. They took proportionately larger 

 quantities of blood than were used in the experiments upon the dog- 

 fishes. Moreover, days and weeks elapsed between the periods when the 

 blood was tested. 



In each of the following cases, after the spinal cord was destroyed, the 

 fish was placed in a tank of sea-water. Then samples of blood were 

 taken at intervals for the freezing point determination. Eesults were 

 obtained from nine fishes which ranged in length from 56 cm. to 124 cm. 

 and in weight from 538 gm. to 6482 gm. For each freezing point de- 

 termination, about five cubic centimeters of blood were taken from the 

 smaller fishes and ten cubic centimeters from the larger. The entire 

 amount of blood in mammals is stated to be one-thirteenth of the body 

 weight. It is also known that a loss of one-half of this amount does not 



