80 



The Journal of Heredity 



It is absolutely necessary to get a 

 complete history. I recently saw a child 

 with sporadic cretinism. In answer to 

 the usual questions, the mother stated 

 that no other members in either branch 

 of the family were similarly affected, 

 and as far as she knew all the children 

 began to talk and walk at the usual 

 time. However, on further questioning 

 it was found that two of the father's 

 sisters had been operated upon for 

 goiter and an older brother of the pa- 

 tient, who was 16 years of age, weighed 



225 pounds. Here, at least, there was 

 an indication of a family tendency to 

 disturbances in the thyroid gland and 

 the endocrine system. If a number of 

 physicians, engaged in the different 

 specialties, would collect a large num- 

 ber of complete pedigrees in those dis- 

 eases and conditions which are known 

 to be frequently inherited, I believe a 

 large amount of valuable data can be 

 obtained, and much light could be 

 thrown on many of the obscure prob- 

 lems of etiology. 



Influence of Environment on Tree Growth 



When I bought my property here 

 there existed upon it a certain number 

 of "blue gum" trees (Eucalyptus glo- 

 huhis) all planted at the same time, in 

 1880, and of different degrees of develop- 

 ment, according to their position (on 

 natural unbroken soil, on loose deposits 

 of "made" soil, and in more or less 

 sheltered places). 



One of them, now, like the others, 

 37 years old, has a circumference of 

 83^ cm. at the height of 1 m. It was 

 planted in close proximity to a dense, 

 wild vegetation of evergreen and decid- 

 uous oaks and other trees and on the 

 upper edge of the slope, where these 

 trees grow. The other blue gtuns are of 

 very unequal development according to 

 their position, and scjme of them, those 

 planted in soil brought on and conse- 

 quently loose to a great depth, are what 

 I should take to be normal in size, when 

 growing in a dry climate and receiving 

 no irrigation. 



But I have planted a few blue gums 

 myself, and one of them, planted in 

 hard soil, never broken except for the 

 small hole in which the seedling was 

 planted, is now 223^^ years old and 

 measures 23^2 rneters in circumference, 

 at one meter height above the ground. 

 The secret of the great development of 

 this specimen is that water is running 

 nearly always at the foot of this tree. 



Jvverybody can assure himself of the 

 enonnous difference in development of 

 annual plants (.so easy to control), ac- 

 cording to more or less favorable condi- 



tions, but when it is a question of wild- 

 growing trees, facts are not always so 

 prominent as to attract attention. 

 Plants of whatever kind will often con- 

 tinue to live under most unfavorable 

 conditions but making hardly any 

 growth; and even species famous for 

 extraordinarily rapid de\^elopment as the 

 blue gums will accommodate themselves 

 to such a state. The quickest growing 

 palms of temperate climates, the Wash- 

 ingtonias (California fan-palms), fur- 

 nish another example in my garden, 

 where a certain nimibcr planted on the 

 edge of a slope covered with native tree 

 vegetation have remained stationary, 

 the size of two year old seedlings, for 

 sixteen years. 



It seems very necessary to distinguish 

 between the development of a tree in 

 highly favorable conditions, as the arbor 

 vitae shown in the picture growing in a 

 park (p. 161, Journ.vl of Heredity, 

 April, 1917) and wild trees usually 

 growing in crowded condition and hav- 

 ing to compete for light and root space 

 with numerous others. Only such live 

 in what I should call "nonnal" condi- 

 tions, because so uninfluenced by man. 

 The most perfect development of a 

 plant can only take place in quite excep- 

 tional conditions in the wild state, else- 

 where it must be sought for where man 

 has stepped in to favor the plant in 

 question. 



.\. RoHERTSON PROSCnOWSKV, 



Pare "Les Tropiques," 

 Nice, France. 



