AM.CEBM. 85 



ment, successively emit a greater or smaller number of lobes, none of 

 which are precisely alike, but, after having appeared for an instant, each 

 successively re-enters into the common mass, with which it becomes 

 completely incorporated. Variable in their respective forms, these lobes 

 present appearances quite different in the several genera. They are 

 more or less lengthy, more or less fringed, and often branching ; some- 

 times they are filiform, sprouting in all directions over the animal 

 mass, which rolls in the liquid like the husk of a small chestnut. 



If we ask how these animals are nourished, in which no digestive 

 apparatus can be distinguished, the question is difficult to answer. 

 It is thought that they are nourished by simple absorption, and by 

 absorption only. In the interior of the gelatinous mass which constitutes 

 the animals, however, granules and microscopic portions of vegetables 

 are frequently discovered. " We can conceive," says Dujardin, " how 

 these objects have penetrated to the interior, if we remark, on the one 

 hand, that in creeping on the surface of the glass, to which they adhere 

 very exactly, the Amoebse can be made to receive, by pressure, foreign 

 substances into their own bodies, by means of the alternate contrac- 

 tion and extension of the various parts natural to them, and, on the 

 other hand, that the gelatinous mass is susceptible of spontaneous 

 depressions here and there near to or even at the surface of the 

 spherical cavities, which successively contract themselves and disappear 

 in connection with the strange body which they have absorbed." 



The Amoebss are often observed to be tinted red or green ; this 

 arises from the special colouring matter which has been absorbed into 

 its mass. 



The question arises, How do these creatures, so simple in their 

 organization, propagate their species ? 



We believe that they are chiefly multiplied by parting with a lobe, 

 which, in certain conditions, is enabled to live an independent exist- 

 ence, and develop itself, thus forming a new individual. This is what 

 naturalists term generation by division fissiparism or fission. The 

 absence of a nutritive and reproductive apparatus in the Amoebse, and 

 the want of stability in their forms, explain how nearly impossible 

 it is to characterise as species the numerous individuals daily met 

 with in infusions of organic matter in stagnant water. In order to 

 distinguish some of the groups, Dujardin bases his descriptions upon 

 their size and the general form into which they expand. 



