july — sept. 1857.] between ihe Animal and Plant. 



mine more closely the consanguinity of the two kingdoms, beginning 

 with the bii ih of the members of both in a simple cell, and then con- 

 sidering what important parts cellular structures play throughout all 

 the economy of their future life. BufTon on beholding the smallest 

 animal of the existence of which we are aware, the little monad that 

 swarms in stagnant water, imagined that all vegetable and animals were 

 built up of these minute cells. True to its unchanging philosophy, 

 which laughs at every new truth, the world sneered at Button's impro- 

 bable idea ; but we know now that the sage naturalist saw truth in 

 his dreams. The smallest of the Infusoria, the most minute Cryp- 

 togam are but simple cells living an independent isolated life, and 

 every living structure however complex, however strange, has had a 

 cellular origin, and is indebted for its growth and maintenance to 

 the modification and development of cells.* The cell consists of an 

 enveloping membrane or cell wall, that encloses a peculiar fluid and 

 nucleus or cell-germ. True we find numerous examples of cells 

 that do not exhibit even the trace of a nucleus, but from these it 

 may cither have been removed by absorption, or it may be destin- 

 ed to appear at some future era of their existence. The modes of 

 Cytogenesis are various, but nearly all agree in being common to the 

 animal and vegetable. To the older Physiologists the subject of 

 reproduction was fertile in speculation and romance, and it was only 

 when the theory of cells and their development became known, 

 that we were able to read its history in the earlier and more myste- 

 rious stages. In the higher animals and plants, the process is com- 

 plicated in accordance with the general plan of organization, but 

 as we approach the simple infusorial animal or cryptogamic plant, 

 we can with facility explore the plan of nature's grand secret. Here 

 new generations originate in accordance with the laws of Cytoge- 

 nesis, the nucleus of the parent preparing a future race, or some 

 of the other systems obtaining by which the old cell begets the new. 



Remembering then that Cytogenesis is in all cases the necessary 

 part of the process of reproduction, if from the generation of the 

 lower species we proceed upwards to the more perfect animal or 

 plant, we shall find that any complication of plan is merely sup- 



* The exceptions to this general rule do not demand special notice. 



