June 22, 1916] 



NATURE 



343 



INHERITANCE IN ROVING AND IN 



ROMANTIC TYPES.^ 



T X his interesting study Dr. Davenport deals 



-L first with those not unfamiliar types who 



innot settle down, who run away from home and 



■ hool, who disappear suddenly and are next 



card of at the ends of the earth. When the im- 



)ulse is well-marked those whom it sways are 



known as rovers, and the periodic or prevailing 



domination of life by the wandering impulse may 



be called nomadism. It occurs in various forms 



and degrees, but the term nomadism should not 



be used too widely if it is to be of any use. Thus 



Meunier's classification includes legitimate nomads 



(like peddlers and missionaries), delinquent 



nomads (like fugitives from justice), nomads of 



ethnic origin (like gipsies and crusaders), as w^ell 



as nomads of morbid origin (who are "rovers" 



in the strict sense). But this net has been too 



widely cast, and the suggestion that the rovers are 



necessarily morbid is unfortunate. The truant 



ay become a scholar-gipsy and the stowaway a 



reat explorer. 



According to Dr. Davenport, "nomads, of all 

 lads, have a special racial trait — are, in a proper 

 nse, members of the nomadic race. This trait 

 .s the absence of the germinal determiner that 

 makes for sedentariness, stability, domesticity." 

 From the data of a hundred family histories (some 

 of which seem to us far from convincing as illus- 

 trations of true roving), the investigator concludes 

 that 



nomadism is probably a sex-linked recessive mono- 

 hvbrid trait. Sons are nomadic only when their 

 mothers belong to nomadic stock. Daughters are 

 nomadic only when the mother belongs to such stock 

 and the father is actually nomadic. When both 

 parents are nomadic, expectation is that all children 

 will be. 



The wandering impulse is frequently associated 

 with various kinds of periodic behaviour, such as 

 depression, migraine, epilepsy, and hysteria, but 

 Dr. Davenport is probably right in concluding 

 that these merely permit the nomadic impulses to 

 assert themselves. We do not feel at all con- 

 vinced, however, by the argument that nomadism 

 in man is of the same order as the regularised rest- 

 lessness of migratory birds, or that it is the re- 

 assertion of a fundamental human instinct, nor- 

 mally inhibited by the conditions of civilisation. 



The second study deals with the inheritance of 

 temperament, more especially of the "romantic" 

 and "classic" types, that is to say, the quickly- 

 reacting and the slowly-reacting, the feebly-inhi- 

 bited and the strongly-inhibited. In the old ter- 

 minology the choleric and nervous were contrasted 

 with the phlegmatic and melancholic ; in the new 

 Terminology the " hyperkinetic " are contrasted 

 with the "hypokinetic." Politically, Dr. Daven- 

 port tells us, the contrast spells radical and con- 

 servative ; in any case, the dualism runs through 

 our whole population. 



The investigator is well aware that our tempera- 



1 ''The Feeblv Inhibited. Nomadism, or the Wandering Impulse with 

 Special Reference to Heredity. Inheritance of Temperament." By C. B. 

 Davenport. Pp.158. (Washington : Carnegie Institution, 1915.) 



XO. 2434, VOL. 97] 



mental outlook is profoundly affected by a com- 

 plexity of conditions, such as the secretion of tlie 

 suprarenal bodies, the blood-pressure, the state of 

 the arterial walls, the adequacy of digestion and 

 toxin-elimination, the state of the eyes (as Gould's 

 well-known studies show), as well as by such un- 

 considered trifles as an ambition, a passion, an 

 enthusiasm, an ideal ; but he is not afraid to launch 

 the hypothesis that there is in the germ-plasm a 

 factor, E, which makes for excitability, while its 

 absence means calm ; that there is another factor, 

 C, which makes for cheerfulness, while its absence 

 "permits a more or less periodic depression." 



This hypothesis is supported by an analysis of 

 the pedigree-charts of eighty-nine families. There 

 is interesting evidence of similarity of tempera- 

 ment in "identical twins." As regards marriage 

 it is pointed out that " these twain " rarely have 

 "the same zygotic temperamental formula," which 

 is doubtless providential. As regards suicide it 

 is shown that the hyperkinetic and the hypokinetic 

 types are consistent even to the end, for they keep 

 to their distinctive methods. The factorial hypo- 

 thesis seems to work well in certain cases, but we 

 must confess that the theory of a factor C, " which 

 makes for normal cheerfulness of mood," appears 

 to us an incredible simplification of the facts of 

 life. 



PROF. SILVANUS P. THOMPSON, F.R.S. 

 '^F'HE sudden and unexpected death of Prof. 



A Silvanus Thompson will be deeply regretted 

 by a large and distinguished circle of personal 

 friends, as well as by the many engineers, elec- 

 tricians, and others who, either directly in his 

 classes, or indirectly through his books and writ- 

 ings, have come under the influence of his teach- 

 ing. A many-sided, cultivated, and highly gifted 

 man of untiring industry', possessed of an almost 

 unique knowledge, not only of the highways and 

 byways of science itself, but also of its history 

 and the history of its creators, Prof. Thompson 

 held a distinguished position in the scientific 

 world. 



During the past three centuries scientific facts 

 have been accumulating so rapidly and on so vast 

 a scale that no one could to-day honestly pretend, 

 with Francis Bacon, that he took all knowledge 

 for his province. Nor would it be possible nowa- 

 days for any single individual to be, like Leonardo 

 da Vinci, the master, not only of every branch of 

 science and engineering, but also of literature and 

 the arts. Prof. Thompson, however, if he fell 

 short of reaching the unattainable, was a real 

 master in many separate intellectual fields. In 

 the sciences of electricity, magnetism, and optics, 

 and in other branches of physics, he made dis- 

 coveries and did original work of his own, besides 

 much other work in the way of elucidating and 

 popularising what was done by others. Gifted 

 with a peculiar charm of manner, a pleasantly 

 resonant voice, great clarity of diction, and an 

 immense facility for finding the proper words and 

 expressions, his lectures were always a pleasure 

 to listen to, particularly as, in addition to his 



