311 



iüfluence of rennet and that it is insoluble iu chloroform , ben- 

 zine, ether and alcohol. Further Haycraft made out that its ac- 

 tion does not agree with that of »peptone" though both sub- 

 stances hinder the coagulatiou of the blood. 



Dickinson however has suggested the active principle of the 

 leechextract is to be classed in the group of the albumoses ') , 

 but he does not come to a positive conclusion in this matter. 



I believe, there is more reasou to regard the substance, which 

 enables the leech to prevent the clotting of the blood , as a 

 nucleoproteid. Some experiments were made in the following way : 



The heads of several leeches were hardened in strong alcohol, 

 then dried , ground and finally extracted with destilled water 

 (10 cc. water for the head of one leech). The extract was acidu- 

 lated with acetic acid, by means of which it becarae cloudly, as 

 Dickinson already found. The praecipitate was separated from the 

 fiuid with the centrifuge , solved in water with a very small quan- 

 tity of ammonia and again praecipitated by acetic acid. This treat- 

 ment was repeated once more and the praecipitate then washed 

 with destilled water, alcohol aud ether, and dried. Extremely 

 small quantities of this substauce, solved in Na Cl 0,7 \ with 

 tracé of soda were sufficiënt to prevent the clotting of blood. 

 When this substance was solved in H Cl 0,2 "/q and digested with 

 pepsiue and hydrochloric acid, there came a praecipitate which 

 was readily soluble in alcohol , and incinerated with soda in ni- 

 trum , gave a fair reaction of phosphor with molybdenic acid. 



I have not continued these researches, because I failed in suf- 

 ficiently purifyiug the acetic acid praecipitate. The leechextract 

 is always more or less tinged, as is also remarked by Haycraft 

 aud by Dickiuson , with the pigmeut of the skin. Now this pig- 

 meut is always praecipitated with the nucleoproteid by acetic 

 acid. Because the acetic acid praecipitate , as appears from the 

 quautity of nucleiue to be prepared thereof, consists chiefly of 

 a nucleoproteid, aud because this praecipitate possesses the cha- 



1) Journal of Physiol. Vol. XI. p. 566. 



