308 APPLIED IMMUNOLOGY 



Transfusion of Blood 



There are many conditions under which transfusion of 

 blood from one individual to another is of great value. 

 Among the commonest of these are: Loss of blood follow- 

 ing operations and accidents, severe ansmia from various 

 causes, hemorrhage in typhoid fever, gastric hemorrhage, 

 hemorrhage of the new-born, and postpartum hemorrhage. 

 The introduction of new blood fulfils three functions : ( 1 ) It 

 stops the hemorrhage; (2) replaces lost blood; (3) assists 

 in overcoming any infection present by supplying fresh 

 complement and antibodies. 



In transfusion the person yielding the blood is known 

 as the donor, wliile the person receiving it is known as the 

 recipient. In selecting a donor, it is important that his blood 

 be compatible with that of the recipient. Incompatibility 

 of the two bloods may be manifested in haemolysis or agglu- 

 tination of one case by the other, producing grave symptoms 

 or even fatal results. Haemolysis of the blood of either the 

 donor or the recipient in transfusion is a pathological phe- 

 nomenon and causes haemogiobinuria which may be fatal. 

 Th*. 'e is evidence that cases in which haemolysis occurs in 

 vitro will also show haemolysis in vivo, and a prehminary test 

 of the bloods is therefore important in the selection of a 

 donor. 



It has not been proved that agglutination of the red 

 blood-cells of the donor by the serum of the recipient, or 

 vice versa, gives rise to serious results, and this is therefore 

 not regarded as a contra-indication to the transfusion. In 

 case, however, there should be a considerable range of 

 selection of donors, one should be selected if possible whose 

 blood is not agglutinative. 



In every case where practicable, the blood of the donor 



