368 



The Journal of Heredity 



a pure line by self-pollination will 

 necessarily have to be extended over a 

 very long series of years. Alost of 

 the so-called "improved" varieties of 

 pecans were originally found growing 

 wild and have been propagated asex- 

 ually ever since. 



On exhibit at the Horticultural Show 

 of the A. and M. College of Texas 

 in 1922. was a display of thirty-six 

 distinct types of pecans, produced by 

 thirty-six different trees that were 

 grown from seed, all produced the 

 same year by a single mother pecan 

 tree, the original San Saba. Of the 

 thirty-six samples only four are con- 

 sidered as good as, or better than the 

 mother tree. Two of them, the Texas 

 Prolific and Western Schley, have been 

 introduced as named varieties. In size 

 of nuts there is a rather uniform gra- 

 dation from those as large as beans to 

 those over two inches in length. No 

 correlation between size of nut and 

 thickness of shell is evident. Some of 

 the larger nuts have very thin shells, 

 while some of the smaller ones have 

 extremely thick ones, and vice versa. 

 The accompanying picture gives only a 

 inadequate idea of the difference be- 

 tween these varieties, since size and 



shape are the only qualities which show 

 up well in pictures. There are also 

 marked differences in flavor, proportion 

 of kernel to shell, readiness with which 

 kernel separates from shell, and habits 

 of growth of the tree from which the 

 nuts came. 



The man who planted the pecans 

 and expected the progeny to be exact 

 reproductions of the San Saba variety 

 convinced himself by this demonstra- 

 tion that propagation of pecans by seed 

 is not a reliable method ; and he is now 

 perpetuating his standard varieties by 

 budding and grafting. He continues 

 to plant pecan seeds only in the hope 

 of obtaining chance seedlings which 

 will be good enough to introduce to the 

 public as named varieties. 



Thus it will be seen that the propa- 

 gation and improvement of the pecan 

 is governed by the very same principles 

 which govern the apple, pear, and other 

 fruit and nut trees. There is this one 

 difference, however : the development 

 of the pecan is so recent that there still 

 remain greater opportunities of finding 

 sui^erior seedlings than is the case with 

 the fruits and nuts which have been 

 longer cultivated by man. 



The Doctrines of Sidis 



Nervous Ills, Their Cause and 

 Cure, by Boris Sidis, M. D. Pp. 

 379; price $3. Boston, Richard G. 

 Badger, 1922. 



In this volume Dr. Sidis gives an 

 extended popular presentation of his 

 thesis that mental and nervous diseases 

 are due to perversions of the funda- 

 mental instincts of self-preservation 

 and fear. He describes the satisfactory 

 results of his treatment of such diseases 



by the hypnoidal state. Two chapters 

 devoted to heredity and eugenics re- 

 spectively are superficial and bigoted. 

 The chapter discussing eugenics is in 

 considerable part made up of a diatribe 

 against eugenists which the author 

 evidently admires enough to quote ver- 

 batim (but without citation) from one 

 of his earlier volumes. Numerous in- 

 teresting case histories are presented. — 

 P.P. 



