§25 



an opinion about it is, however, very difficult ; leucocytes are always 

 among a great number of red cells and the sections are always 

 thicker than one red or white cell. Anyhow, it seems very probable 

 to me that this must liappen. For: 



1. the red cells disappear after 6 — 8 days. 



2. in vitro they are easily phagocytated. 



3. The subcutaneous cellflaid and the leucocyte extract do not 

 contain an nnspecitic haemolysin (Schneider : 1. c. ; this concerns 

 polynucleons (mikrophages) as well as mononucleous cells (macrophages). 



1 have tried after one or two- days to cut out the swelling (after 

 injecting the sensitized (agglutinated) cells), and then to spread them 

 out on a coverglass: these preparations too gave bad images ; princi- 

 pally by the stickiness of the substance: I did not see a distinct 

 phagocytosis. 



I have here always spoken about sensitized cells without wishing 

 to form an opinion about the open question of identity between 

 amboceptors and opsonins and tropins. (Neufeld ^) Satschensko ■)). 



The following experiment will show that there can be amboceptor 

 as well as tropins in the subcutaneous cellular tissue. A piece of 

 cottonwool was entered under the skin of the abdomen of a prepared 

 rabbit (against sheep'erythrocytesl and the fluid was examined after 

 some hours : in vitro it strongly stimulated the phagocytosis of 

 sheep-erytrocytes bj^ rabbit-leucocytes. 



As a summary we can draw the following conclusions: 



1. When using red corpuscles loaded with amboceptor as antigen 

 one should remove all surplus of serum. 



2. Sensitized and agglutinated red corpuscles, when injected sub* 

 cutaneously, remain in the same place for a long time; non-treated 

 cells are soon led away. 



3. This will most probably be the consequence of the agglutination, 

 not of the sensitizing. The same happens to non-specific agglutination 

 — also when it concerns the animal's own cells. 



4. With prepared animals possessing agglutinin, the cells injected 

 also remain in the place where they have been injected. So agglu* 

 tination in vitro also takes place; this is not the case with animals 

 which only possess amboceptors (opsonins) and no agglutinins. 



5. The subcutaneous lymph contains very little or no complement, 

 it does contain amboceptor, agglutinin, opsonin (tropin). 



The above will show my experiments not yet to be complete. 

 They require to be completed as to the question to what 



1) Arbeiten aus den Kais^rl. Gesundh. Bd. 25, 27 en 28. 



2) Arch. Sc. biol. St. Petersburg. XV, biz. 145 1910. 



22 

 Proceedings Royal Acad. Amsterdam. Vol. XVII. 



