Charles Todd 129 



examination of a family of sheep (consisting of the father, mother and 

 three lambs) showed the interesting ftxct that the corpuscles of one 

 lamb resembled almost exactly those of the mother, whilst the corpuscles 

 of the other two lambs had the characters of the father. 



From what has preceded we see that it can be definitely proved 

 by tests made in vitro that in the case of a warm-blooded animal 

 the red blood corpuscles of any one individual are different from those 

 of any other individual of the same species (always excepting the case 

 of close blood-relations). Moreover the corpuscles of one individual 

 when introduced into the blood-stream of another individual are re- 

 garded by their new host as foreign bodies and are treated as such. 

 A consideration of this very striking fact at once leads to speculation 

 as to whether this is not merely one example of a general law holding 

 for all the cells of the body. Unfortunately the other cells present 

 much greater experimental difficulties than the red blood cell, whose 

 delicate stroma renders it accessible to the quite extraordinarily sensitive 

 methods of haemolysis ; we have, however, a considerable aniount of 

 indirect evidence in favour of this view, derived mainly from the results 

 of transplantation of the various tissues in man and other warm-blooded 

 animals. Schiine, in his most interesting work {Die Jieteroplastische 

 •and homooplastische Transplantation), summarises the results of other 

 observers and also gives an account of his own extensive researches on 

 this subject. Perhaps the most striking results given are in connection 

 with skin grafting. It is now generally recognised that whereas skin 

 grafts replanted on to the individual from which they were taken 

 (autoplastic transplantation) succeed with ease ; those planted on to 

 a different individual of the same species (homoioplastic transplantation) 

 are exceedingly rarely, if ever, successful, unless the two individuals 

 happen to be blood-relations. Schone woi-king with mice found that 

 homoioplastic transplantation failed almost as regularly as autoplastic 

 transplantation succeeded. His experiments with blood-relations showed 

 that transplantation between brothers and sisters and from the child to 

 the mother were possible ; but, curiously enough, in the few cases in 

 which it was tried, transplantation from the mother to the child did 

 not succeed. This result is particularly interesting in connection with 

 the haemolytic experiments recorded above on the difference between 

 the red blood corpuscles of the cow and her calf In the transplantation 

 of bone Axhausen's most careful experiments show that autoplastic 

 transplantation succeeds much better than homoioplastic. Rehn has 

 shown that the same holds good for the transplantation of fatty tissue. 



