Babcock and Lloyd: "Somatic Segregation" 



89 



implies a mechanism for segregation in 

 somatic mitosis. 



2. Bud sports and chimeras are 

 attributable to somatic mutations. 

 These, like germinal mutations, are 

 caused by specific factor changes which 

 occur without any known irregularity 

 in chromosome behavior. 



3. In the case of deciduous and 

 persistent cal\TC lobes in the Le Conte 

 pear and Transcendant crab it is shown : 



(a) That exfoliation of a calyx lobe is 

 conditioned by failure or retardation of 

 the secondary thickening of the lobe. 



(b) That to assume "somatic segrega- 

 tion" in the case of nearly one-fourth 

 of the calyx lobes on a tree is impossible 

 in view of the general regularity of the 

 process of mitosis. 



(c) That deciduousness and persist- 

 ency are not necessarily inheritable 

 variations. 



(d) That a reasonable explanation 

 of the phenomena in question is that of 

 increased variability in an already 

 variable character due to the complex 

 hybrid nature of the varieties in 

 question . 



New Publication Devoted to Mental Hygiene 



The National Committee for Mental 

 Hygiene has undertaken the publica- 

 tion of a quarterly magazine of about 

 160 pages, with the title "Mental 

 Hygiene," the first number dated Janu- 

 ary, 1917. Its scope is announced as 

 follows : 



''Mental Hygiene will present to a wide 

 circle of readers in as non-technical a 

 way as possible articles on the practical 

 management of mental problems in all 

 relations of life. Today, as never 

 before, attention is being directed to 

 mental factors in the problems of the 

 individual and of society. These fac- 

 tors are of paramount importance in the 

 study and practical management of 

 delinquency, crime and inebriety. We 

 no longer ignore the fact that education 

 must meet the needs of children who 

 present special difficulties of adaptation. 

 The widespread determination to control 

 feeblemindedness raises questions of 



economics, law, and medicine which 

 demand the most thoughtful considera- 

 tion. New ideals in the care and treat- 

 ment of those suffering from mental 

 disorders are imposing new obligations 

 upon the public authorities. The recog- 

 nition of preventable causes of mental 

 diseases challenges us to seek in the 

 field of mental hygiene victories com- 

 parable to those achieved in general 

 hygiene and sanitation. 



"Mental Hygiene will bring depend- 

 able information and a new inspiration 

 to every one whose interest or whose 

 work brings him into contact with 

 problems of this kind. No other peri- 

 odical exists for the express purpose of 

 serving these ends. Of interest to all 

 thoughtful readers, to physicians, law- 

 yers, educators, clergymen, public of- 

 ficials, and students of social problems, 

 the magazine will be of especial 

 value." 



Material for Plant Breeders 



Plant breeders will find a great deal 

 of valuable material described in the 

 Sixth Annual List of New Plant Intro- 

 ductions, which was issued this month 

 by the Office of Foreign Seed and Plant 

 Introduction, Bureau of Plant Industry, 

 U. vS. Department of Agriciilture, Wash- 

 ington, D. C. More than 500 species 

 and varieties of plants, most of them 

 of economic importance or relatives of 

 economic plants, are listed. Seeds or 



rooted plants can be supplied to those 

 who are interested either in breeding 

 new forms or in testing new introduc- 

 tions. It will be necessary, however, 

 to apply at once, since the amount of 

 material available is in many cases 

 limited, and none is carried over from 

 season to season. All those who are 

 interested in new plants and have 

 room to grow them should write for 

 this list. 



