ON THE WANING OF WEISMANNTSM. 



329 



the finest and strongest progeny. Professor Zavitz, of the Guelph College, 

 Ontario, has also obtained astonishing results by breeding from the largest 

 and best grain of Joanette oats that he could discover in the whole of his 

 harvest. 



With plants there can hardly be any effect of precept and example 

 such as are possibly exercised by the worker bees during the education of 

 the young brood. 



Yet if a leaf's trials and experiences result in a change of its internal 

 contents ; if, in consequence of its struggle for existence, a new colour 

 or enzyme or a new "something" should be formed internally, which 

 initiates new, or upsets old, chemical balances, then surely this new 

 development must affect the whole plant and, above all and especially, 

 the young pollen and growing embryo for whose support the whole 

 physiology seems to be designed. 



This idea of "physiological states," which is due to Jennings and 

 Klebs, involving, as it does, the direct action of the outside world, seems 

 really to promise a more satisfactory explanation of the process of evolution 

 than any that has as yet been offered. 



That such direct influences are really effective would hardly be denied 

 by any practical gardener or by field botanists. Professor Klebs himself 

 managed to change blue-flowered campanulas into white ones simply by 

 altering the conditions of cultivation. 



The numerous recent papers which deal with Mendelian inheritance 

 have clearly brought out the fact that colouring matters, or the enzymes 

 which initiate them, are regularly transmitted. 



It follows therefore that not only the healthy vigour due to successful 

 effort but also any special acquisition in the way of colour or ferment 

 brought about by the struggles of the leaves and roots for life must 

 necessarily influence the pollen and egg cells. 



Instead of the experience (mental or instinctive) put into the feeding 

 and education of young bees by the worker, we must assume a chemical 

 stress in the physiological state of the plant. 



Those who still uphold Weismannism manage to reconcile their views 

 with many awkward facts of observation by assuming some indirect action 

 perhaps not very unlike what we have tried to explain. 



But surely it would be more satisfactory to delete "germplasma " from 

 our botanical theories and to eradicate from our minds the benumbing 

 prejudices of Weismannism. 



