1893.] Presents. 569 



plasma by passing a stream of C0 2 * through it, it appears to me that 

 this might be very naturally explained by assuming that we are 

 dealing with a direct reversal of the process which occurs when 

 peptone is injected into the blood. The CO 2 coagulation in peptone 

 blood would upon this hypothesis be due to a precipitation of cell- 

 fibrinogen in the plasma under the influence of an excess of weak 

 acid. Such a precipitation of cell-fibrinogen in the plasma would be 

 in some sort an equivalent of an addition of cell-fibrinogen to peptone 

 plasma, and would, therefore, naturally inaugurate coagulation. 



The coagulation of peptone plasma in vitro by COz would be closely 

 paralleled by the fact that intravascnlar coagulation after injection 

 of cell-fibrinogen occnrs, as I have pointed out (' Journ. of PhysioL/ 

 1890), only in the vascular areas where C0 2 is present in excess. 



The precipitation of cell-fibrinogen in peptone plasma under the 

 influence of CO 2 would further have a close analogy in the precipita- 

 tion of its congener caseinogen from diluted milk by the addition 

 of excess of dilute acids. 



Presents, February 9, 1893. 

 Transactions. 



Berlin : Gesellschaft fur Erdkunde. Verhandlnngen. Bd. XIX. 



Nos. 910. 8vo. Berlin 1892 ; Zeitschrift. Bd. XXVII, 



No. 4. 8vo. Berlin 1892. The Society. 



Brisbane : Queensland Musenm. Annals. No. 1. 8vo. Bris- 

 bane 1891. The Museum, 

 Cambridge, Mass. : Museum of Comparative Zoology. Bulletin, 



Vol. XXIII. No. 4. 8vo. Cambridge 1892 ; Annual Report, 



1891-92. 8vo. Cambridge 1892. The Museum. 



Chapel Hill, N.C. : Elisha Mitchell Scientific Society. Journal. 



Vol. IX. Part 1. 8vo. Raleigh 1892. The Society. 



Cordova : Academia Nacional de Ciencias. Boletin. Tomo XI. 



Entrega 4. 8vo. Buenos Aires 1889. The Academy. 



Edinburgh : Royal Scottish Society of Arts. Transactions. Vol. 



XIII. Part 2. 8vo. Edinburgh 1892. The Society. 



Irkutsk : Societe Imperiale Russe de Geographic (Section de la 



Siberie Orientale). Izvestiya. Vol. XXIII. Nos. 1, 3. 



[Russian.] 8vo. Irkutsk 1892 ; Zapiski. Vol. I. Nos. 1 3. 



Vol. II. Nos. 1 2. [Russian.'] 8vo. Irkutsk 1889-90; 



Zapiski (General Geography Section). Vol. I. No. 1. Vol. 



II. No. 1. [Russian.] 8vo. Irkutsk 1890-92. The Society. 



* This coagulation does not occur in any other plasma; neither does it occur in 

 blood which has been kept liquid by an addition of peptone in vitro. It may be 

 noted that the addition of even 8 per cent, of peptone to blood in vitro does not 

 entail any destruction of leucocytes. 



