fle 



1-edlty 

 tory 



SCIENTIFIC SIDE-LIGHTS 



306 



lished until after his death. Instincts, he 

 shows, can be acquired. Birds which were 

 once perfectly fearless of man now display 

 the usual terror, since the oceanic islands 

 which they inhabit have been visited or 

 settled, and transmit their prudent instinct 

 to their offspring. On the other hand, while 

 at first frightened by passing railway trains, 

 they soon learn that these novelties betoken 

 no danger, and so in time the birds along- 

 side the lines view them with the most per- 

 fect equanimity. The sheep, which in Spain 

 are taken every summer to pastures in 

 another part of the country, acquire by and 

 by an instinct for this artificial migration, 

 which is displayed by curious uneasy mo- 

 tions, so strong that about the time when 

 they ought to be off it requires all the 

 vigilance of the shepherds to prevent them 

 escaping, and there are cases in which the 

 journey has been performed, the animals 

 reaching their old feeding-grounds without 

 assistance. BROWN Nature-Studies, p. 21. 

 (Hum., 1888.) 



149O. The Question Sta- 

 ted Government and Philanthropy In- 

 volved. It is obvious that we can produce 

 important changes in the individual. We 

 can, for example, improve his muscles by 

 athletics and his brain by education. The 

 use of organs enlarges and strengthens 

 them; the disuse of parts or faculties 

 weakens them. And so great is the power 

 of habit that it is proverbially spoken of 

 as " second nature." It is thus certain that 

 we can modify the individual. We can 

 strengthen (or weaken) his body; we can 

 improve (or deteriorate) his intellect, his 

 habits, his morals. But there remains the 

 still more important question which we are 

 about to consider. Will such modifications 

 be inherited by the offspring of the modi- 

 fied individual? Does individual improve- 

 ment transmit itself to descendants inde- 

 pendently of personal teaching and ex- 

 ample? Have artificially produced changes 

 of structure or habit any inherent tendency 

 to become congenitally transmissible and to 

 be converted in time into fixed traits of 

 constitution or character? Can the philan- 

 thropist rely on such a tendency as a hope- 

 ful factor in the evolution of mankind? 

 the only sound and stable basis of a higher 

 and happier state of things being, as he 

 knows or ought to know, the innate and 

 constitutionally fixed improvement of the 

 race as a whole. If acquired modifications 

 are impressed on the offspring and on the 

 race, the systematic moral training of in- 

 dividuals will in time produce a constitu- 

 tionally moral race. . . . But if acquired 

 modifications do not tend to be transmitted, 

 if the use or disuse of organs or faculties 

 does not similarly affect posterity by in- 

 heritance, then it is evident that no innate 

 improvement in the race can take place 

 without the aid of natural or artificial se- 

 lection. BALL Are the Effects of Use and 

 Disuse Inherited? p. 7. (Hum., 1891.) 



1491. 



Views of Spencer 



and Mill Brain-states Transmissible. This 

 doctrine [of heredity of acquired char- 

 acters] was first explicitly put forth by 

 Mr. Herbert Spencer, in whose philosophical 

 treatises it will be found most ably de- 

 veloped. I am glad to be able to append 

 the following extract from a letter which 

 Mr. John Mill, the great master of the 

 experiential school, was good enough to 

 write to me a few months since, with ref- 

 erence to the attempt I had made to place 

 " common sense " upon this basis (Contem- 

 porary Review, February, 1872): "When 

 states of mind in no respect innate or 

 instinctive have been frequently repeated, 

 the mind acquires, as is proved by the 

 power of habit, a greatly increased fa- 

 cility of passing into those states; and 

 this increased facility must be owing to 

 some change of a physical character in the 

 organic action of the brain. There is also 

 considerable evidence that such acquired fa- 

 cilities of passing into certain modes of 

 cerebral action can, in many cases, be trans- 

 mitted, more or less completely, by inherit- 

 ance. The limits of this power of trans- 

 mission, and the conditions on which it 

 depends, are a subject now fairly before the 

 scientific world, and we shall doubtless in 

 time know much more about them than we 

 do now. But so far as my imperfect knowl- 

 edge of the subject qualifies me to have an 

 opinion, I take much the same view of it 

 that you do, at least in principle." CAR- 

 PENTER Nature and Man, lect. 6, p. 197. 

 (A., 1889.) 



1492. HEREDITY OF AN IDIOT Four 

 Steps from Immorality to Imbecility Alco- 

 holic Excess from the Outset. Morel has 

 traced through four generations the family 

 history of a youth who was admitted into 

 the asylum at Rouen in a state of stupidity 

 and semi-idiocy; the summary of which may 

 fitly illustrate the natural course of degen- 

 eracy when it goes on through generations. 



First generation: Immorality, depravity, 

 alcoholic excess, and moral degradation, in 

 the great-grandfather, who was killed in a 

 tavern brawl. 



Second generation: Hereditary drunken- 

 ness, maniacal attacks, ending in general 

 paralysis, in the grandfather. 



Third generation : Sobriety, but hypochon- 

 driacal tendencies, delusions of persecutions, 

 and homicidal tendencies in the father. 



Fourth generation: Defective intelligence. 

 First attack of mania at sixteen; stupidity 

 and transition to complete idiocy. MAUDS- 

 LEY Body and Mind, lect. 2, p. 45. (A., 

 1898.) 



1493. HEREDITY MOLDS CHARAC- 

 TER Improvement and Adaptation. The set- 

 ting-dog is taught to set; he squats down 

 and points at the game; but the habit is 

 an acquired one a mere trick of education. 

 What, however, is merely acquired habit in 

 the progenitor is found to pass into instinct 



