OF VITAL PHENOMENA 177 



GANOIDS 



Acipehser isturio 76 



Lepidosteus osseous 49--52 



Polyodon spathula 486-.50 



INVERTEBRATES (excepting marine) (blood -+- body juices) 



Anodonta cyignea 2 



Astacus fluviatilis 8 



Dytiscus marginalis 57 



Hirudo medicinalis 4-43 



Dragon flies 65 



The osmotic pressure of the blood plasma must be imitated 

 in any solution used to wash the corpuscles, as otherwise cytolysis 

 (hemolysis) may result. If NaCl solutions are desired, .95 per 

 cent is used for mammals, reptiles and birds and .65 per cent for 

 frogs. A 1 per cent CaCl 2 (anhydrous) solution, or .74 per cent 

 KC1, or .75 per cent NaCl has a A = .465. In order to reduce the 

 toxicity of the NaCl, the solutions described at the end of the 

 chapter are used. If cane sugar is used where a non-electrolyte 

 is desired, about ten times as much is weighed out as in case of 

 NaCl for an equal volume of solution (see Fig. 30). Sugar 

 solutions are slightly toxic, probably on account of the H ions 

 the sugar dissociates. An absolute non-electrolyte has not been 

 found. It is possible that a small proportion of urea added to 

 the sugar solution might reduce the H ion concentration suffi- 

 ciently. 



S* 



Fig. 29. Viscosimeter for a drop of blood. A little hirudin or oxalate 

 is placed in one bulb, which is filled with blood. The tube is grasped 

 with forceps and inverted. The viscosity is proportional to the time re- 

 quired for the blood to leave the bulb. 



The blood in passing through the capillaries of the body under- 

 goes many changes, not all of which are well understood. The 

 effect of C0 2 on the blood is more complicated than was at first 

 supposed. When C0 2 is bubbled through blood the H ion con- 

 centration is increased in the plasma and the OH ion concentra- 

 tion reduced, but, contrary to what might be expected, the 

 titratable alkalinity is increased. This is partly explained by the 

 fact that the CI ions are reduced by the substitution of carbonates 

 for chlorides. Koeppe (1897) put forward the following hypothe- 

 sis: The C0 2 enters the corpuscles and combines with the 



