842 GEORGE E. MINOT AND ARLIE V. BOCK 



anaphylatoxin. A foreign blood plasma could thus easily act as an accel- 

 erator of this action and suddenly convert the circulating blood into a 

 toxic substance. 



Another factor to be considered is the influence of an anticoagulant 

 such as sodium citrate. Experience with citrated blood, as stated before, 

 has resulted in a much larger percentage of reactions of mild type than 

 when blood is used to which no substance has been added. Drinker and 

 Brittingham have suggested that this may in part be due to the action 

 on the red cells of sodium citrate which promotes hemolysis. 



It is certainly true that the less blood is altered the less chance there 

 is that these reactions will occur. Such alterations are often beyond con- 

 trol, for at least a small number of these reactions will develop despite 

 scrupulous technic in transfusion. Even so, neat technic with rapid 

 transfer -of blood will permit the fewest possible reactions. 



By no manner of means is it to be thought that transfusions with 

 citrated blood should not be done, because these reactions are usually 

 slight and rarely alarming, and fatality, if it occurs, must be very rare. 

 However, reactions appear to be less frequent when blood without an anti- 

 coagulant is used, so that in certain instances it may be preferable not 

 to give citrated blood. 



VIII. Methods of Transfusion 



Indirect methods of transfusion have entirely replaced the original 

 direct methods. The simplicity of the indirect methods, together with the 

 ease with which hemolysis may be avoided, has led to the general use of 

 blood transfusion. Such methods are designed to transfer blood either 

 as unaltered whole blood or blood mixed with an anti-coagulant, especially 

 sodium citrate. 



The chief advantage of transfusion of blood to which no substance has 

 been added is that it produces fewer reactions, not due to recognized 

 incompatibility, than citrated blood. In view of the reactions associated 

 with transfusion, it is theoretically desirable to transfuse blood in its 

 natural state as far as it lies within technical means to do so. The dis- 

 advantages encountered in the transfer of blood to which no substance has 

 been added consist in difficulties with a more cumbersome technic for 

 transfusion, usually requiring two or more persons, and more experience 

 than is necessary with the citrate method. There is also a more frequent 

 necessity for cutting down on veins when certain methods for transfusing 

 blood without anticoagulant are employed. In the hands of experts, these 

 difficulties are not troublesome, and in such cases transfusion of unaltered 

 whole blood is the method of choice. 



Descriptions of methods for the transfusion of blood to which no 



