BLOOD RELATIONSHIP 295 



are seen, for example, in the destruction of the alien 

 corpuscles in cases of transfusion with heterologous 

 blood. The idea that first prompted physicians to 

 transfuse the blood of a sheep or other lower animal into 

 the exsanguinated human vessels was erroneous because 

 it assumed that the red bloods were all alike. We now 

 know that the disappointing results following such 

 treatment depend in part upon the inappropriate char- 

 acter of the heterologous blood of which the patient can 

 make little use, and which places him under the dis- 

 advantage of being compelled to dissolve and destroy 

 all the formed elements as well as to rid himself of offen- 

 sive proteids in the serum. It has been found by experi- 

 ence that physiological salt solution is more satisfactory 

 in that it fills the vessels, and enables the heart to con- 

 tinue its work until blood regeneration begins, without 

 introducing anything offensive into the body. Even 

 when transfusion is practised from one individual to 

 another of the same species one human being to an- 

 other the result is not always so satisfactory as might 

 be hoped, because there are individual as well as specific 

 and racial differences, and the normal blood of one human 

 being may in rare instances prove prejudicial to another 

 because of the presence of preformed isolysin by which 

 the corpuscles are destroyed, or because of the presence 

 of offensive proteids. 



When the subject of grafting is considered, it will be 

 found that the blood relationship of the scion and the stock 

 in both plants and animals probably has much to do 

 with determining the success or failure of the experiment. 

 Tissue taken from one animal and grafted upon another 

 survives or is destroyed in large measure according to 

 the blood relationship of the animals concerned. So 

 sensitive are the tissues in this particular that, among 

 animals successful grafting can rarely be performed 

 when specific differences obtain among them. 



It also appears as though this matter of blood relation- 

 ship with its affinities, indifferences, or repugnances 



