SOME MOOT POINTS AV NATURAL HISTORY. 247 



naught when we consider the case of a fungoid growth the 

 jEthalium of the botanist which grows upon putrefying 

 plants, and which is frequently found in tan-pits. This 

 fungus if fungus it be when undergoing certain develop- 

 mental changes, actually becomes endowed with powers of 

 movement ; feeds after the fashion of its kind on living 

 matter, that is, on animals or other plants ; and has, more- 

 over, been well ascertained to be capable, like an animal, of 

 taking in solid food, plants, as every one knows, possessing 

 no mouths, but subsisting on liquid or gaseous nutriment. 

 ^Ethalium and its neighbours form in reality a collective 

 bete noire of the modern biologist, and at present, therefore, 

 we are positively unable to return any answer whatever to 

 the question, " Is sethalium an animal or a plant?" 



Such examples might be multiplied almost indefinitely 

 from the index expurgatorius of the botanist and zoologist, 

 but enough has been said to show that the mere surround- 

 ings of the subject of animal and plant nature are any- 

 thing but plain and well-defined. No less clear is the fact 

 that whilst the higher groups of animals and plants are 

 readily separable, the lowest members of the two great 

 groups of living beings merge together in a union of form 

 and functions which modern science is at present totally 

 unable to dissolve. The ordinary idea, that the separation 

 of animals from plants, so clearly effected in the higher life 

 of either side, may be carried out in the domain of lower 

 existence, is thus seen to be entirely erroneous. And when 

 the demand of science for a philosophical definition of an 

 animal or a plant, which shall apply, as such a definition 

 should, to all animals and to all plants alike, is submitted 

 to the naturalist, he is forced to own that at present he is 

 unable to say definitely what are the essential characters of 

 the one kingdom or of the other. 



The subject before us presents some exceedingly 

 interesting features, if examined somewhat in detail and 

 from the popular point of view, which attaches to the details 

 of form, power of motion, and the like, a high importance in 



