Animal Morphology. 141 



These observations are upon an extremely limited scale, 

 yet they have included most of our forest and garden trees, 

 and, when carefully examined, appear to be sufficiently 

 uniform to claim a short notice, when passing in review 

 morphology in its general bearings upon vital force, showing 

 that there is a general interdependence of parts, in a whole, 

 throughout all its general bearings. 



But, as regards the approximation of identity in relation 

 to the two kingdoms, there is but one general impression 

 here maintained, and that is, that in cell development, 

 throughout its endless morphologies and differentiations, 

 there is nothing that really stands equivalent to a tripartite 

 membrane, or any cell possessing a really genuine con- 

 tractile power, self-existent in the tissues of the vegetable 

 kingdom. All assimilations to contractile tissues are all so 

 many modes of utilizing external nature, so as to bring 

 about peculiar kinds of mechanism ; such as the sensitive 

 plant, Venus's fly-trap, the opening by night or closing by 

 night of certain flowers, and the twisting of leaves to moist 

 wind and exposing their stomata, etc., etc. The rising of the 

 sap is due alike to the expansive effects of heat, and, may be 

 also, to chemical changes, effected by the chemical rays of 

 the sun, both aiding to compel a vacuum, Nature's great 

 horror; and, for fear of falling into any quagmires from this 

 source, she has secured a most perfect mechanical parasite, if 

 such aterm may be generalized, in her great agent, atmospheric 

 pressure; add again to this capillary attraction, and the law of 

 diffusion of fluids, especially aided by membrane, as shown 

 by Graham and Duhamel in osmosis and dialysis, and then 

 we have all the agents necessary to perpetuate successive 

 changes and progress, in increased decay and in onward 

 development, which are required after the first start of the 

 true vegetable fructification of any special kind of ovum. 



As there is no real contractile force in the vegetable 



