128 THE BLOOD 



GLOBULOCIDAL AND OTHER PROPERTIES OF SERUM. 



Cytolysis. It has been known for some time that the sera of certain 

 animals when injected into the circulation of animals of another species will 

 cause destructive changes in the blood-corpuscles, accompanied by symptoms 

 of poisoning, which may even end fatally. These results served to bring into 

 disrepute the use of foreign blood in transfusion, which has consequently 

 been practically abandoned. This discharge of the hemoglobin of the red 

 blood-corpuscles and solution in the plasma (laking) is now included in the 

 general term Cytolysis, and more specifically known as Hemolysis. Agents 

 which produce such an effect are known as hemolytic or hemotoxic agents. 

 Sera of one species are not hemolytic for blood of all other species, but the 

 serum of one animal may be made to acquire such properties for the blood 

 of another. 



This adaptation is brought about in the following way: For instance, 

 the blood of the guinea-pig, which is not normally lytic for the red cells of the 

 rabbit, may be adapted to the latter by previously, at several successive 

 intervals (three to seven days) injecting into the abdominal cavity or sub- 

 cutaneous tissues of the guinea-pig small quantities of rabbit's blood. If 

 now a small quantity of serum be obtained from the guinea-pig by the usual 

 methods and mixed in a test tube with some of the rabbit's blood diluted 

 with physiological salt solution, hemolysis occurs. That is, the coloring 

 matter of the rabbit's red blood-cells goes into solution and the cells appear 

 under the microscope as shadow corpuscles or ghosts, devoid of hemoglobin. 

 Such an artificially produced hemolytic serum is only lytic for the blood of 

 the animal species for which it has been adapted. It is true that it may also 

 show slightly lytic properties for closely allied species. It has therefore been 

 suggested as a possible valuable aid in determining relationships of various 

 animal species. 



Concerning the nature of the lytic substance, it has been found that it 

 probably consists of two bodies acting conjointly, for if the serum be heated 

 to 56 C. for a short time, its lytic powers are lost, but may be restored by 

 adding a little serum of another animal of the same species which has not 

 been adapted, and whose serum is consequently not in itself lytic. Of these 

 two bodies, therefore, one is stable and is formed only in the adapted serum, 

 while the other is more unstable or labile (destroyed at 56 C.) and exists 

 normally iri the blood plasma. The former is known as the immune body 

 and the latter as alexin. Lysis occurs only when both are present at the same 

 time, and not through the agency of one or the other singly. 



This cytolytic adaptation has been extended to include other cells besides 

 the red blood-corpuscles. Thus in a similar manner leucolytic, hepatolytic, 

 nephrolytic, and a number of other lytic sera have been developed. 



It is further possible, under certain circumstances, that substances may 



