821 



at tlie same time agglutinated) cells. Tn the tirst place T used a 

 colloidal solution of SiO, for it. 



All the red bloodcells I used (rabbit, guinea pig, horse, cattle, dog) 

 were agglutinated by it. be it in various concentration. Only the 

 SiOg had no effect ; it caused neither swelling, nor leucocytosis. It 

 had been prepared I13' saponifying Siliciinnethylether (Kahlbaum) with 

 greatly diluted hydrochloric acid. Colloidal SiO.^ prepared in aditferent 

 way had the same etfect. Now one might object against this 

 experiment that the SiO., not only agglutinates the bloodcells, but 

 that it also sensitizes them ; for together with guinea pig serum in a 

 great quantity, it can dissolve some kinds of blood. Tlierefore I took 

 refuge to the vegetable agglutinins which are found in the bean, 

 pea, lentil, and in the seeds of Datura Stramonium. In all these 

 cases the result was (he same: the bloodcells always remained there ; 

 the conjunctiva also showed the wellknown bluish-red change of 

 colour after some days, and histologically the inuige was always the 

 same. It goes without saying that with all those experiments the 

 sterility was taken into consideration as much as possible. '). 



In order to make quite sure, however, that only sensitized and 

 agglutinated corpuscles did not show the phenomenon, I examined 

 some thirty rabbits out of my collection on haemolysin and agglu- 

 tinin against sheep-erythrocytes, and 1 really found some sera which 

 did contain haemolysin, but only little agglutinin. I repeated the expei'i- 

 ments with these sei'a ; but the results were not very distinct : there 

 sometimes was a difference, but it was not big enough to draw a 

 certain conclusion from it. 



This is because all the sera employed were rather weak (ambo- 

 ceptor 7.50 — Vioo) ^"0 so a rather big quantity of serum was necessary 

 (zb 3 cm.) to sensitize the cells. Normal rabbitserum generally con- 

 taining some agglutinin, we did not succeed in this way 'm obtaining 

 a suspension of sheep-erythrocytes which are sensitized but little or 

 not agglutinated. Yet I can communicate one experiment which came 

 out rather well : 



Serum rabbit 73 titre amboceptor Vso ^'^ry little agglutinin. 

 147 ,, ,, nearly \\^^ much 



V2 ccm. sheep-erythrocytes is digested with ± 3 ccm. serum 73, 

 just as 72 ccm. with =t 3 ccm. serum 147. The suspensions are 

 centrifuged and the corpuscles are taken up in 1 ccm. saltsolution. 

 Erythrocytes 73 are injected on the right, erythrocytes 147 on the 



1) I did not use ricine because the poisonous qualities of this substance would 

 have injured the inaage. 



