STUDIES OX H^MOLYSIXS. 59 



of guinea-pigs. Heating the serum for half an hour to 55 C. 

 causes this property to be lost, owing to the destruction of the com- 

 plements. On the other hand, one frequently finds horse sera, by 

 themselves unable to dissolve the erythrocytes of rabbits or guinea- 

 pigs, which are able through their content of complement to complete 

 the inactive interbody of the goat serum and make this a complete 

 haemolysin. According to Buchner's views, only a single alexin is 

 concerned in haemolysis. We therefore next studied the question 

 whether the interbodies which act on the blood-cells of rabbits and 

 guinea-pigs are identical. For this purpose we first determined the 

 dose of inactive goat serum which, on reactivation by the addition 

 of sufficient horse serum, was able to dissolve a certain amount on 

 rabbit or guinea-pig blood-cells. On the basis of these data this 

 amount of rabbit blood in physiological salt solution was mixed with 

 the required amount of inactive goat serum and after standing a 

 short time at room temperature the mixture was centrifuged. The 

 result was as follows: The clear fluid mixed with additional rabbit 

 blood cells and the activating horse serum showed no trace of solvent 

 property; the red blood-cells, originally separated by centrifuging> 

 dissolved completely under the influence of horse serum. In a 

 parallel series of experiments the clear fluid was mixed with guinea- 

 pig blood. In this, complete solution ensued. 



From these experiments the conclusion follows that rabbit blood 

 combines with an interbody present in goat serum, and does so, 

 in fact, completely; whereas the interbbdy acting on guinea-pig blood 

 is not at all fixed by the rabbit blood. By means of this elective 

 absorption, therefore, it is positively determined that normal goat 

 serum contains two interbodies, one acting on rabbit blood and the 

 other on guinea-pig blood. 



The question at once arose whether these interbodies possess 

 a single complement in common or whether there is a special comple- 

 ment for each. Only after considerable labor were we able to decide 

 this question experimentally. We were finally able to determine 

 that in the filtration of normal goat serum through Pukall filters, 

 the first portion (6-10 cc.) possesses a markedly different solvent 

 power for rabbit and guinea-pig blood. We herewith reproduce 

 an experiment of this kind. 



0.15 cc. of goat-serum previous to filtration was able to dissolve 

 completely 2 cc. of a 5% mixture of guinea-pig blood, while 0.2 cc. 

 serum was able to dissolve the same amount of rabbit blood. After 



