STUDIES ON HAEMOLYSIS. 27 



the purpose of obtaining serum. This serum, as we had antici- 

 pated, never showed a trace of haemoglobin coloration. As early 

 as the second day, a slight solvent action for the blood of goats 4 and 

 5 was developed. A drop of the blood allowed to fall into the undi- 

 luted serum of buck A suffered partial solution, so that after the 

 blood-corpuscles had sedimented, the serum remained slightly tinged 

 with red. By the fifth day the solvent property had increased 

 considerably; 0.5 cc. serum completely dissolving 1.0 cc. of the 

 5% blood-mixture of goat No. 4. By the seventh day the action 

 had reached its maximum. 0.3 cc. serum produced complete solu- 

 tion (No. 4); 0.07 a just appreciable effect. 



As we now had at our disposal a sufficient amount of hsemolysin., 

 we sought to determine whether this hsemolysin dissolved all goat 

 blood-corpuscles without exception. We found that of nine goats 

 which we examined, the majority were markedly sensitive to this 

 haemolysin. Thus goats Nos. 1, 2, 4, 5, 6, and 9 were highly sen- 

 sitive; two goats, Nos. 3 and 8, somewhat less so; and only one, 

 No. 7, (which had previously been treated for some time with the 

 expressed juice of eel muscle,) showed so slight a susceptibility that 

 even undiluted serum failed to cause strong solution. 



After noting these results it was important to determine the 

 behavior of the blood-cells of this buck toward the haemolysin of 

 his own serum. If a drop of blood was added to the serum, in vitro, 

 not even a trace of solution occurred. These blood-cells then were 

 entirely insusceptible to the hsemolysin of their own serum, as had 

 already been indicated by the absence of haemoglobin coloration 

 in the freshly drawn serum. 



If we designate the specific haemolysin developed by the injec- 

 tion of blood of foreign species as heterolysin, then we must designate 

 the haemolysin due to the injection of blood of the same species as 

 isolysin. In no case, however, and this is to be emphasized, are 

 we here dealing with an autolysin, i.e. a tysin which dissolves the 

 blood-cells of the animal in whose serum it circulates. However, 

 such a condition is not at all a matter of course, and the question 

 arises why the isolysin in this case does not also functionate as auto- 

 lysin. 



The toxins as well as the haemolysins can act only when they 

 are anchored by certain haptophore groups, the receptors, whereby 

 the action of the poisons is concentrated on the cells possessing these 

 receptors. If these groups are lacking, the poison has no point of 



