THE BLOOD. 93 



cording to WOOLDRIDGE, a reciprocal action between A- and B- 

 fibrinogen. An exchange of lecithin from the .4-fibrinogen to the 

 ^-fibrinogen takes place. 



HALLIBURTON has opposed weighty arguments to this theory. 

 It is also difficult to find in WOOLDRIDGE'S discussion conclusive 

 proofs for the above views, and the experiments by which they are 

 supported are interpreted with difficulty. The entire theory is 

 chiefly based on experiments with "peptone-plasma;" but such 

 plasma acts differently in certain respects than ordinary plasma. 

 It should be especially mentioned that, while ordinary plasma and 

 an ordinary fibrinogen solution act similarly on heating, the pep- 

 tone-plasma shows quite different behavior. The peptone-plasma 

 when diluted with water, or on passing C0 2 through it, or on the ad- 

 dition of a little acid, also acts, when the so-called ^4-fibrinogen has 

 not been removed, like a plasma in which the ordinary fibrinogen 

 ((7-fibrinogen) has been partly converted into an intermediate step 

 between fibrinogen and fibrin. Until the differences existing be- 

 tween ordinary plasma and peptone-plasma shall have been more 

 thoroughly tested and generally accepted it will be difficult to give 

 an unambiguous interpretation of observations made on peptone- 

 plasma. 



FREUND seeks the reason for the coagulation in a separation 

 of calcium phosphate whereby a part ,of the previously-dissolved 

 albuminous bodies becomes insoluble as fibrin. By the adhesion 

 existing before the coagulation the alkali phosphate of the form- 

 elements passes over to the plasma richer in lime salts and forms 

 calcium phosphate. If the amount of this last is so large in the 

 plasma or any other coagulable liquid that it cannot be kept com- 

 pletely in solution, then, according to FREUND'S views, the separa- 

 tion of the excess is the cause of a part of the albuminous bodies 

 becoming insoluble, or, in other words, is the cause of the coagula- 

 tion. It is a well-known -fact that fibrin and fibrinogen yield an 

 ash containing calcium phosphate, and that lime salts facilitate 

 coagulation or cause a coagulation in liquids poor in ferment; and 

 it is also well known that rennet ferment cannot cause a coagula- 

 tion in a casein solution if there is a lack of lime salts. There is 

 no question about the lime salts being of great importance in the 

 fibrin coagulation ; but that a separation of calcium phosphate is 



