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V. — Transmutation of Form in certain Protozoa. 

 By Metcalfe Johnson, M.E.C.S.E., Lancaster. 



Plate LXXXV. 



In the *M. M. J.' for April, 1870, I have ventured to remark 

 that " Monas and its congeners became at once important as agents 

 in removing dead cells, and in their pl&ce supplying us with green 

 verdure which is springing up around us on every side." Everyone 

 must have observed that universal greenness which, after the lapse 

 of a few weeks, spreads more or less over every weather-exposed 

 surface, large or small. Sir Humphry Davy, writing forty years 

 ago, says, " A polished surface of a building or a statue is no sooner 

 rough than the seeds of hchens and mosses which are constantly 

 floating in the atmosphere make it a place of repose, grow and 

 increase," If we examine a few of the green growths upon these 

 surfaces differing from one another in their surroundings, or 

 " choses exterieures," such as moisture, hght, temperature, &c., we 

 shall And one composed of a green dust, to which the name of 

 Chlorococcus has been applied ; another, a green scum upon the 

 surface of a liquid, which has received the name of Euglena; a 

 third, forming patches of dark green slime upon old walls, and 

 called Oscillatoria ; a fourth, Lynghya ; a fifth, Vaucheria ; a 

 sixth, Schidzonema, and so on, A more detailed examination of 

 these separately-named products, and a study of their life-history, 

 leads to the opinion that they are all (more or less) stages of de- 

 velopment of some one common source, which it is the object of the 

 present remarks to identify as the monad, or pin-point source of 

 life, which has been pointed out by Dr, Bastian and others as the 

 earhest form in which we recognize living matter. 



In a review of nature we are insensibly led to observe an 

 apparent unity of all its parts into a continuous whole. Thus, in 

 tracing black to white, we find no point of divergence perceptible 

 to the senses. Positive electricity only differs relatively from 

 negative. The animal differs from the vegetable, but the difference 

 is insensible. In order to establish a view of nature such as is 

 here proposed, it will be necessary to inquire what evidence we 

 have before us — first, of a general, and, secondly, of a particular 

 kind. 



Professor Graham, in his ' Liquid Diffusion appHed to Analysis,' 

 asks, " Can any fact more strikingly illustrate the maxim that in 

 nature there are no abrupt transitions, and that distinctions of class 

 are never absolute ? " 



In an article called " Higher and Lower Animals," akeady re- 

 ferred to in this Journal, it is said, " Bather may animal life be 

 Ukened to a great tree with countless branches spreading widely 



