CYTOLYSINS 117 



nomenclature are most frequent in the literature. We have elected to 

 use the terms amboceptor and complement because of our belief that 

 these terms have attained the more widespread usage. Complement 

 appears in the blood of many species, but may be very small in amount 

 or absent from certain species. Certain complements may operate 

 with the amboceptors of only a few species, whereas others may act 

 with amboceptors of a large number of species. Within a given species 

 different individuals may possess complement in variable quantity, and 

 it may vary at different times in the same individual. The complement 

 of guinea-pig blood is usually large in amount and applicable to the 

 amboceptors of a considerable number of other species. Complement 

 does not appreciably change in amount by the ordinary processes 

 of immunization. 



Immune Hetero-hemolysins. Hemolytic amboceptors may be 

 natural to a blood or may be developed by immunization. Autolysins 

 and isolysins may be produced but with great difficulty and variability. 

 Isolysins may be present normally, notably in man. Heterolysins may 

 be found normally and can be readily produced by artificial immuniza- 

 tion. Bordet produced heterolysins by intraperitoneal injection of ery- 

 throcytes. They may also be induced by the subcutaneous and by the 

 intravenous routes of inoculation. Two important conceptions of the 

 mode of action of the amboceptor have been proposed. Bordet, Metch- 

 nikoff and the French school consider the action to be in the nature of a 

 sensitization or fixation of the antigenic cells, so that they are more 

 readily acted on by the complement, in somewhat the same fashion 

 that a mordant prepares a cell so that it will stain more readily. Ehr- 

 lich and Morgenroth and the German school consider the amboceptor 

 as a link which brings together antigen and complement ; in other words, 

 in their conception the amboceptor possesses two binding groups, a 

 cytophilic and a complementophilic group, each capable of acting as a 

 specific receptor. In order to discuss the various theoretical con- 

 siderations more clearly, it is essential that the well-established facts in 

 regard to hemolysis be presented as they are ordinarily demonstrated 

 in a practical way. 



Preparation of Immune Hemolysins. The Blood Antigen. In immuniza- 

 tion for the production of a hemolysin it is necessary to select the animals to 

 be used. The rabbit is usually chosen as the animal to be immunized because 

 of the fact that it is easily available, relatively inexpensive, and yields a fairly 

 large amount of blood. In selecting the animal whose blood-corpuscles are to 

 be used for the production of hemolysin, convenience again plays a part. The 

 sheep is the animal most commonly employed, although the goat is equally use- 

 ful. Reasonably large amounts of blood can be secured from such animals at 

 short intervals of time, without deleterious effects. Dog blood is unsatisfactory 

 because the corpuscles do not resist standing for any length of time. The cat is 

 undesirable because of its relatively small size. In order to secure blood from 

 a goat or sheep the animal is either strapped on a board, or may be held by a 

 skilled attendant. The neck is shaved over the jugular vein, the area washed 

 with soap and water, cleansed with alcohol, and the vein distended by pressure 

 over the jugular bulb at the base of the neck. The blood is collected through a 

 fairly large needle into a sterile flask containing glass beads or fragments of 

 glass tubing. Rotation of the flask or shaking during the collection and con- 

 tinued shaking for five or ten minutes after the collection completely defibrinates 



