The Transition from Animals to Plants. 291 



minute animalcules, with a red eye point, and a transparent 

 mouth place ; that they are not in fact distinguishable from 

 Ehrenberg's Microglena monadina ; these bodies, however, 

 are animals only for a time. At least they grow into vege- 

 table threads, the lowest joint of which still exhibits the red 

 eye point. This phenomenon, which Kutzing assures us he 

 has ascertained beyond all possibility of doubt, puts an end 

 to the question of whether animals and plants can be dis- 

 tinguished at the limits of their two kingdoms, and suffi- 

 ciently accounts for the conflicting opinions that naturalists 

 entertain as to the nature of many of the simpler forms of 

 organization. 



Such being the case, it is not worth attempting to decide 

 whether the lowest forms of structure belong to the one 

 kingdom or the other ; it will be sufficient that they have been 

 regarded as plants by many eminent naturalists. 



It is in this microscopical cellular state of existence that 

 the Animal kingdom ends and the Vegetable commences. It 

 is from this point that the naturalist who would learn how 

 to classify the kingdom of plants must take his departure. 

 He perceives that those species which consist of cells either 

 independent of each other (Protococcus uredo), or united into 

 simple threads (Conferva monilia), are succeeded by others 

 in which the threads collect into nets (Hydrodictyori), or 

 plates (Ulva), or the cells into masses (Laminaria agaricus) ; 

 peculiar organs make their appearance, and, at last, as the 

 complication of structure increases, a leaf and stem unfold as 

 distinctly limited organic parts. Kutzing cut to pieces the 

 marine animal called Medusa aurita, washed the pieces care- 

 fully in distilled water, put them into a bottle of distilled 

 water, corked it close, and placed it in a window facing the 

 east. The bits of Medusa soon decomposed, and emitted a 

 very offensive odour, during which time no trace of infusoria 

 was discoverable. After a few days, the putrid smell dis- 

 appeared, and myriads of Monads came forth. Shortly after, 

 the surface of the liquid swarmed with extremely small 

 green points, which eventually covered the whole surface; 

 similar points attached themselves to the sides of the bottle. 

 Seen under a microscope, they appeared to be formed of 



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