506 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



consider the applications of the results to different subjects, particu- 

 larly those of an anthropological nature. 



It is a fundamental fact that blood properties have a remarkable 

 permanence. Their individual stabihty may even be regarded as 

 absolute; a man never changes his group under any circumstances 

 whatever. We already have observations covering 25 years, and we 

 know that age never modifies the reactions, nor does any physiological 

 condition. Illness has no effect, nor have treatments of the most 

 varied kind, in spite of what may have been said to the contrary. 

 X-rays, hko those of radium, or repeated anaesthesia, produce no 

 effect. Lastly, the group is not changed even after a transfusion 

 from the blood of another group ; and the case is actually recorded of 

 a subject of group AB (universal receiver) having undergone 75 trans- 

 fusions with blood from each of the four groups without suffering any 

 modification of his own blood. 



A second characteristic of blood properties is the precocious 

 manner in which they are differentiated. The agglutinogens appear 

 before the agglutinins. They are sometimes discoverable in the second 

 month of embryonic hfe. One can in any case always detect them 

 during the last weeks preceding birth, and so plainly that it is alwa3'^s 

 possible, normally, to know to what group a now-born child belongs. 



If blood properties are fixed and precocious, they do not manifest 

 the same degree of strength in all subjects. Agglutinins, hke agglu- 

 tinogens, differ in strength according to individuals, race, and age. It 

 has been recorded, for example, that the power of agglutinins, always 

 very weak at birth, increased up to 30 years of age, to decrease after 

 40; and that it was greater amongst Malays than amongst Europeans. 



The fact of belonging to a given group is a hereditary character- 

 istic. It would be impossible hero to give even a rapid outline of the 

 mechanism of heredity. What is essential is to Icnow that in a child 

 no agglutinogen can appear which is not present in the blood of one 

 or other of its parents. If the father and mother belong to group A, 

 all the children may belong to group A; if they belong to group 0, 

 all the children will belong to group 0; if the parents do not belong 

 to the same group — if, for example, one is A and the other B — the 

 children ^vill differ and be A, B, AB, or 0.' Recognition of these 

 facts has resulted in curious applications of them. It has made it 

 possible, for instance, to restore to their respective mothers newly 

 bom infants wliich had been mixed up immediately after birth. Above 

 all it has been used in medico-legal practice to investigate paternity. 



Attempts have been made to establish a connection between blood 

 properties and other morphological or physiological characters of the 



• It may be added that according to Bernstein (1925) and Snyder (1925) blood groups Inherit as 3 multiple 

 allelomorphs corresponding to the agglutinogens, A and B being dominant in association with a similar 

 recessive R, and not as 2 independent pairs of factors, as was formerly thought. 



