AN ENQUIRY INTO THE FORMATION OP HABIT IN MAN, 157 



consciousness is not an exhibition of force neither is the ^vill. It 

 is extra-physical. 



" In tlie paper which I had the honour of reading before the In- 

 stitute (VoL xxvi) I suggested a possible anatomical explanation 

 of the formation of habit. It is at present but a hypothesis, and we 

 know so little of the ultimate structure of the ' ground substance ' 

 of the nervous system that the hypothesis if not disproved is likely 

 to remain for long unpi-oved ; but the highest magnifications seem 

 to bear out the opinion that the ground substance is a network the 

 strands of whicli are of almost infinite tenuity. It is possible that 

 the passage of impulses inci-eases the width or conductivity of these 

 sti-ands, beats down paths in fact along wdiich subsequent impulses 

 find it easier to travel. 



" I ain glad to find that Dr. Schofield believes in the inheritance 

 of habit, for whether my anatomical explanation be correct or no, 

 habit can only be explained as due to a physical change of some 

 kind in the nerve-tissue, and if the habit be transinissible from 

 parent to child, its transmission is due to the inheritance by the 

 cliild of the alteration in the nerve-tissue acquired by its parent. 

 We need no longer try to settle the much discussed question of 

 whether acquired characters are transmissible by looking out for 

 cases in which gross anatomical changes sucli as shoemaker's chest 

 or carpenter's thumb are inherited by children not brought up to 

 their parents' trade, but we may assert with confidence that the 

 central nervous system as modified by the deliberate choice of the 

 individual tends to be transmitted to his offspring." 



A Member. — May I ask the meaning of the word " sloyd " which 

 occurs in the paper ? 



The Author. — Sloyd is a Swedish method of instructing children 

 in habits of perfect execution. It was invented many years ago, 

 and consists of a sort of carpentry and in making simple things, 

 such as rulers and other things, neatly and accurately, according to 

 a model given to the children. A child may spend a week in 

 making a thing before he makes it of the exact size given ; 

 there are many classes for it now in England, formed with the view 

 of teaching children habits of exact execution. 



Dr. Gerard Smith, M.R.C.S.E. — The question of the hereditary 

 transmission of acquired habits seems to me most important in 

 connection with this paper. Whether we believe, with Darwin, 

 that acquired characteristics arc transmitted to our offspring, or 



M 2 



