508 Messrs Stratton and Gompton, On Accident in Heredity, 



so that one margin overlaps the other*. Accordingly there are 

 possible two kinds of folding, which may be distinguished as 

 right- and left-handed. Considering the series of leaves on a 

 stem, the rule is that the twist of successive leaves is alternately 

 right- and left-handed. If the first leaf is R.H. the second will 

 normally be L.H., the third ii.H., and so on. But a disturbance of 

 this regular sequence often occurs, with the result that two or 

 more leaves of the same twist arise in succession. This inversion 

 of the normal twist of a leaf or leaves appears to be the result 

 of some accidental condition, so slight as to escape notice, but 

 nevertheless sufficient to effect the change from R.H. to L.H., or 

 vice versa. 



The second case was investigated by Lutzf, in an American 

 species of Gryllus, in which one tegmen overlaps the other. 

 Among the $ s Lutz found a total of 742 with the right, 370 with 

 the left, tegmen uppermost. In the </s, however, he found 685 

 rights to only 13 lefts. The reason for this distinction between 

 $ and </ appears to be the smaller amount by which the tegmina 

 overlap in the $ than in the </ : hence a change in the position 

 of the tegmina is more readily effected in the $ than in the j/*. 

 Reversal can be produced by manipulation in the ?, but in the 

 </ discomfort is caused to the insect and the tegmina are soon 

 moved back to their original position^. Here we have a clear 

 example of the effect of accident in producing left-handed 

 members in what appears to be a normally right-handed race of 

 organisms. The difference between the (/" and ? Gryllus in 

 susceptibility to accident is very instructive. 



To return now to the mode of clasping the hands in man. 

 Lutz§ analysed statistics which had been collected by Prof. J. A. 

 Thomson with a view to discovering whether this character is 

 inherited. The following are his results, condensed from his 

 table : 



* See Compton, " On Eight- and Left-Handedness in Barley," in the present 

 number of these Proceedings, p. 495. 



t Canadian Entomologist, xxxviii. p. 207. 



+ The (? s, however, can be made to reverse tegmina while still soft after the 

 moult; and this is perhaps the origin of the few left-handed <? s. 



§ American Naturalist, xlii. 1908, p. 195. 



