160 The Philippine Journal of Science ms 



centimeter. To each tube were added 1.5 cubic centimeters of 

 physiologic salt solution (0.9 per cent) and 0.5 cubic centimeter 

 of a 4 per cent red-cell suspension. The tubes were allowed to 

 stand at room temperature for one hour, and during this time 

 each tube was frequently shaken. After one hour of exposure 

 to room temperature, 0.5 cubic centimeter of ten times diluted 

 complement was added, using the pooled sera of three guinea 

 pigs. The tubes were placed in the incubator for another hour, 

 and then the results were recorded. 



It is evident from the results of these tests (Table I) that 

 none of the human sera showed the presence of natural hemo- 

 lysins against human, monkeys', horses', and guinea pigs' red 

 corpuscles, but the majority of the same sera contained hemoly- 

 sins for sheep's and goats' corpuscles and in a slight degree for 

 cows', carabaos', and rabbits' red cells. 



The one monkey's serum showed lack of hemolysins against 

 human, monkeys', horses', cows', carabaos', rabbits', and guinea 

 pigs' corpuscles, and like the human sera this one serum con- 

 tained a great amount of natural hemolysins against sheep's and 

 goats' corpuscles. 



The human, as well as the one monkey's serum, showed a strong 

 agglutination of carabaos' and rabbits' red cells. As our first 

 experiment was carried out with only one sample of one monkey's 

 serum, we tested in a second experiment the sera of five dif- 

 ferent monkeys. These sera gave identical results with the one 

 sample previously tested, as is shown in Table II. 



Having established the fact that human and monkeys' sera 

 behave in a similar way with regard to hemolysins toward red 

 cells of various animals, we proceeded in the next experiment 

 to test the sera of these animals, including that of man and of 

 monkey, with regard to the presence or absence of natural hemo- 

 lytic amboceptor toward the red cells of each of the animals, in- 

 cluding man. The results of these tests are evident from 

 Table III. The technic applied in this experiment was the same 

 as in previous tests, except the amount of serum used, which 

 was decreased to 0.1 cubic centimeter. 



