BLOOD RELATIONSHIP 311 



ing results following such treatment depend in part upon 

 the inappropriate character of the heterologous blood of 

 which the patient can make little use, and which places 

 him under the disadvantage of being compelled to dis- 

 solve and destroy all the formed elements as well as 

 to rid himself of the offensive proteins in the serum. 

 It has been found by experience that physiological salt 

 solution and Ringer's solution are more satisfactory in 

 that they fill the vessels, and enable 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 proteins. 



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 

 may explain the difficulties attending successful hybridi- 

 zation. The germinal cells of specifically different 

 organisms doubtless possess the same sensitivity to 

 heterologous cells that are manifested by the somatic 

 cells, so that, instead of fertilizing one another, they 

 remain indifferent to one another, repel one another, or 

 perhaps even destroy one another. 



