THE GROUND BETWEEN ANIMALS AND PLANTS. 651 



The authors whom I quote say that they " canuot express " the ex- 

 cessive minuteness of the granules in question, and they estimate 

 their diameter at less than ^-g-oVro ^^ ^^ "^^h- Under the highest 

 powers of the microscope at present applicable, such specks are hardly 

 discernible. Nevertheless, particles of this size are massive when 

 compared to physical molecules ; whence there is no reason to doubt 

 that each, small as it is, may have a molecular structure sufficiently 

 complex to give rise to the phenomena of life. And, as a matter of 

 fact, by patient watching of the place at which these infinitesimal 

 living particles were discharged, our observers assured themselves of 

 their growth and development into new monads. These, in about 

 four hours from their being set free, had attained a sixth of the length 

 of the parent, with the characteristic cilia, though at first they were 

 quite motionless ; and in four hours more they had attained the di- 

 mensions and exhibited all the activity of the adult. These incon- 

 ceivably minute particles are therefore the germs of the Ileteromita ; 

 and from the dimensions of these germs it is easily shown that the 

 body formed by conjugation may, at a low estimate, have given exit 

 to 30,000 of them ; a result of a matrimonial process whereby the con- 

 tracting parties, without a metaphor, "become one flesh," enough to 

 make a Malthusian despair of the future of the universe. 



I am not aware that the investigatoi-s from whom I have borrowed 

 this history have endeavored to ascertain whether their monads take 

 solid nutriment or not ; so that, tliough they help us very much to fill 

 up the blanks in the history of my Ileteromita, their observations 

 throw no light on the problem we are trying to solve Is it an animal 

 or is it a plant ? 



Undoubtedly it is possible to bring forward very strong argu- 

 ments in favor of regarding Ileteromita as a plant. 



For example, there is a fungus, an obscure and almost microscopic 

 mould, termed Peronospora infestans. Like many other fungi, the 

 Peronosporce are parasitic upon other plants ; and this particular Pe- 

 ronospora happens to have attained much notoriety and political im- 

 portance, in a way not without a parallel in the career of notorious 

 politicians, namely, by reason of the frightful mischief it has done to 

 mankind. For it is this Fungus which is the cause of the potato-dis- 

 ease ; and, therefore, Peronospora infestans (doubtless of exclusively 

 Saxon origin, though not accurately known to be so) brought about 

 the Irish famine. The plants afflicted with the malady are found to 

 be infested by a mould, consisting of fine tubular filaments, termed 

 hyphoe, which burrow through the substance of the potato-plant, 

 and appropriate to themselves the substance of their host ; while, at 

 the same time, directly or indirectly, they set up chemical changes 

 by which even its woody framework becomes blackened, sodden, 

 and withered. 



In structure, however, the Peronospora is as much a mould as the 



