28 



The Journal of Heredity 



runic inscriptions of our own Teutonic 

 stock. Languages of this type have 

 actually ceased to exist (except in the 

 Orient) or have modified to the modern 

 style of writing from left to right. This 

 linguistic situation can as readily be 

 explained by resort to heterozygosis as 

 can that of the disappearance of the 

 ancient arboreal types of fern-like plants 

 which flouri.shed so luxuriantly in the 

 coal forests of the Paleozoic. 



The case of the Angiosperms stands 

 by itself, and unfortunately it is this 

 very group upon which the greater part 

 of the genetical theories of the day have 

 their sole support. As our author ])oints 

 out, insect pollination and the cajmcity 

 for cross fertilization are a striking 

 feature of the highest seed plants. This 

 has led to wholesale hybridization, the 

 wide extent of which we are only begin- 

 ning to appreciate. It has been stated 

 that there are scarcely any pure blooded 

 species among the Rosaceae. Recent 

 investigations from the anatomical and 

 reproductive side have made it clear 

 that great numbers of the recognized 

 species of the large genus of pondweeds 

 (Potaniogeton) are in reality hybrids. 

 So accomplished a systematist as Pro- 



fessor Trelease has recently listed more 

 hybrid oaks than recognized species 

 among our splendidly abundant Ameri- 

 can Querci. It is becoming obvious 

 to all but a very few that the genus 

 Oenothera is a plexus of hybrids and not 

 an aggregation of even reasonabh- pure 

 blooded species. 



H.\S STI.MUL.\TIXG EFFECT 



Dr. Lotsy's book will be accepted 

 rather for its stimulating effect than for 

 the accuracy or sufficiency of the facts 

 that it brings to bear. It is now quite 

 clear that hybridization has played a 

 very large part in the evolutionary 

 history of the highest and most useful 

 plants, the Angiosperms; but mechanis- 

 tic and exclusively genetical methods of 

 attack are quite inadequate to resolve 

 the fascinating and complicated prob- 

 lems thus opened. Mendclian analysis 

 alone, and experimental methods by 

 themselves, can lead to no reliable con- 

 clusions. The geneticists will be com- 

 pelled to renew their acquaintance with 

 mor])hology, else, in the words of Mr. 

 Kipling, it will be said of them: 



"They steam for steaming's sake 

 Their port is all to make." 



The Influence of Heredity in Diabetes 



"A Study of the Significance of 

 Heredity and Infection in Diabetes 

 Mellitus" is reported by Dr. John R. 

 Williams, of Rochester, N. Y., in the 

 September issue of the American 

 Journal of the Medical Sciences. He 

 presents 100 case-histories of diabetics 

 and an equal number of non-diabetics, 

 careful inquiry having been made about 

 the relatives in all cases. He finds 

 that "diabetes, arterial disease, and 

 obesity occur with extraordinary fre- 

 quency in the parents and ancestors of 



diabetics, and also that they appear 

 commonly in their progeny." Dr. 

 Williams takes pains to point out that 

 facts of this sort are not crucial enough 

 to be offered as jjroof that diabetes is 

 inherited; "they do justify the con- 

 clusion, however, that a favorable soil 

 for the disease is created in the off- 

 spring of those afflicted either with 

 diabetes or arteriosclerosis, or with both 

 combined; and to a lesser degree with 

 obesity." 



