CAUSE OF COAGULATION OF THE BLOOD. 159 



The next experiments, winch bear directly on the subject 

 under consideration, were made with reference to the impor- 

 tant question, whether the volatile substances escaping from 

 coagulating blood, if passed through fresh blood, would have 

 the effect of retarding or preventing coagulation. The ex- 

 periments on this point are likewise conclusive. The appa- 

 ratus which is used consists of two wide-mouthed bottles, 

 capable of holding about two ounces, and a Wolffe's bottle 

 capable of holding about three pounds. The small bot- 

 tles, fitted with perforated corks, are half filled, and the 

 large bottle nearly filled, with fresh blood. A tube con- 

 nected with a small bellows is introduced into one of the 

 small bottles, passing nearly to the bottom, while a second 

 perforation in the cork is fitted with a short tube which 

 simply allows the escape of air or vapor. The latter is con- 

 nected with a tube passing nearly to the bottom of the Wolffe's 

 bottle through one of the necks, while the other is fitted with 

 a short tube to permit the escape of the vapor. The vapor 

 is then made to pass through the blood in the third bottle by 

 a long tube reaching to the bottom. If air be now gently 

 forced through the apparatus by the bellows, the vapor from 

 the mass of blood (about two pounds is used) in the large 

 bottle will pass through the third, which contains but an 

 ounce of blood. In an experiment of this kind performed by 

 Richardson, " the blood through which the air was first passed 

 coagulated in two minutes ; that in the Wolffe's bottle coagu- 

 lated in three minutes ; while the blood in the third bottle, 

 which for a time received a full charge of the vapor, retained 

 its red color and its fluidity for eight minutes and a half; as 

 long, in fact, as any vapor could be sent through it. When 

 the vapor failed, and air only began to circulate, this blood 

 coagulated feebly, the fibrin separating and floating on the 

 top." 1 



These experiments apparently have but one explanation. 

 As the blood when drawn from the body may sometimes be 



1 Op. cit., p. 268. 



