Dioncea Muscipula, HI lis. 41 



inBrosera, Gardiner concludes that "the protoplasmic utricle" 

 is traversed by pores, and that one effect of contraction " is 

 an increased impenetrability of the primordial utricle and a 

 consequent decrease in the size of the molecular pores." Any 

 contraction must ultimately be referred physically to aggre- 

 gation of certain molecules at the expense of others, though it 

 does not follow in the case of Diotuza, that the main contrac- 

 tion changes can be traced to visible pores. But the writer 

 has already stated that he believes the protoplasm of certain 

 cells exhibits appearances which may point to such a possi- 

 bility, though as yet the observations are insufficient to war- 

 rant special importance being attached to them. It has been 

 shown further, that the protoplasm of most cells is continuous 

 with that of neighbor cells by twenty to seventy-five intercel- 

 lular processes. Proof has been adduced by Batalin, Burdor* 

 Sanderson and others, that closure is due to the inner side 

 of each leaf, becoming less turgid than the outer, owing to 

 migration of liquid from the former. In a Royal Institution 

 Lecture Sanderson x further states : " It has, I trust, been 

 made clear to you that the mechanism of plant motion is 

 entirely different from that of animal motion. But obvious 

 and well marked as this difference is, it is, nevertheless, not 

 essential, for it depends not on difference of quality between 

 the fundamental chemical processes of plant and animal pro- 

 toplasm, but merely on difference of rate or intensity. Both 

 in plants and animals, work springs out of chemical trans- 

 formation of material, but in the plant the process is relatively 

 so slow that it must necessarily store up energy, not in the 

 form of chemical compounds, capable of producing work by 

 their disintegration, but in the mechanical tension of their 

 elastic membranes. The plant cell uses its material continually 

 in tightening springs, which it has the power of letting off, at 

 any required moment, by excitation. Animal contractile pro- 

 toplasm, and particularly muscle does work only when 

 required, and in doing so uses its material directly." 



Now, it may well be asked here, does the cell wall play a 

 specially important part, or is it not rather the case that the 



1 Nature, 1SS2, p. 4 86, et. seg. 



