O ELEMENTARY STRUCTURE 



guished by the term perceptibility. Thirdly ; the mind 

 conceives the wish of grasping that object, and an im- 

 pression is forthwith transmitted to the hand which moves 

 in obedience to this wish. This illustrates a third kind 

 of sensibility, which in common language is termed 

 volition. 



Emily. -I thought that volition was strictly a property 

 of the mind an intellectual operation, whereas, you 

 consider it if I understand aright, a property of the or- 

 ganic tissue. 



Dr. B. Volition no doubt, originates in the mind 

 there is its fountain-head, but since we cannot conceive 

 of its taking place without the action of the nervous tis- 

 sue, it is more convenient to regard the whole act as de- 

 pendent on that tissue, leaving at rest the primary cause 

 by which it is produced. 



Before we close this account of the primitive tissues, 

 we shall have time just to notice very briefly their ulti- 

 mate structure. The microscopical discoveries that 

 have been lately made in reference to the primitive 

 structure of the simple tissues are highly interesting, since 

 they throw 7 new light on the nature oi organization in 

 general. All the simple tissues when examined by a 

 powerful microscope, after being properly prepared, are 

 found to consist of an aggregate of minute filaments each 

 of which is formed by a regular series of globules. 

 These globules whether observed in the cellular, mus- 

 cular or nervous tissue, do not sensibly differ from each 

 other in aspect or dimensions. They are alike, also, in 

 all species of animals, from man even to the Zoophyte. 

 The only difference seems to be in the direction of the 

 filaments, which in the cellular tissue intersect each other 

 in apparently a confused manner. In the muscular tissue 

 the filaments instead of being bent from their line of 

 direction, and running into each other are arranged in 

 parallel rows, separate and disti.ict from one another. In 

 the nervous tissue the globules form lines less zig-zag in 

 their direction than those of the cellular, but deviating 



