154 



THE BLOOD. 



been found, for example, by Andral and Gavarret to be pretty 

 generally increased in the phlegm asise ; but it bears no rela- 

 tion to the richness of the blood. Its proportion is not in- 

 creased always in plethora and diminished in anemia ; and 

 in fact it has been found by Nasse to be increased in animals 

 suffering from hunger. 1 After hemorrhage, which diminishes 

 the corpuscles and albumen, the fibrin is generally increased ; 

 so that the fact of loss of blood, diminishing the force of the 

 heart and increasing the tendency to coagulation, has an in- 

 fluence in the arrest of the flow. 



Circumstances which accelerate coagulation have a ten- 

 dency to arrest hemorrhage. It is well known that exposure 

 of a bleeding surface to the air has this effect. The way in 

 which the vessel is divided has an important influence. A 

 clean cut will bleed more freely than a ragged laceration. In 

 division of large vessels this difference is sometimes marked. 

 Cases are on record where the arm has been torn off at the 

 shoulder-joint, and yet the hemorrhage was, for a time, spon- 

 taneously arrested ; while we know that division of an artery 

 of smaller size, if it be cut across, would be fatal if left to 

 itself. Under these circumstances the internal coat is torn in 

 shreds, which retract, their curled ends projecting into the 

 caliber of the vessel, and have the same effect on the coagu- 

 lation of blood as a bundle of twigs. In laceration of such a 

 large vessel as the axillary artery, the arrest cannot be per- 

 manent, for as soon as the system recovers from the shock, 

 the contractions of the heart will force out the coagulated 

 blood which has closed the opening. 



In our studj of the functions of the body we shall con- 

 tinually see evidences that Nature, not content with simply 

 providing for the ordinary wants of the system, has made 

 provision for extraordinary occurrences and accidents. A 

 striking example of this is the function of fibrin. All the 

 ordinary operations of the body go on perfectly well in 'a 



1 ROBIN and VERDEIL, Chimie Anatomique, tome iii., p. 205. 



