POLYGASTRIC ANIMALCULES. 



541 



the decomposition of which they were evolved ; and others have 

 even supposed them to have arisen from accidental combinations 

 of inorganic elements. As yet, however, somewhat of the same 

 obscurity hangs over their origin, as envelopes the propagation 

 of the Fungi ; since there is some reason to believe that amongst 

 the Polygastrica, also, the same germ may be developed into 

 different forms, according to the character of the infusion from 

 which it derives its support. But these Animalcules are not 

 confined to infusions of organised matter ; they are found in the 

 stagnant waters around our cities ; in the waters of rivers, har- 

 bours, and lakes ; and even, it is believed, in every fluid drop of 

 the ocean. From their minute size and almost universal distri- 

 bution, therefore, we cannot doubt that they are by far the most 

 numerous living beings, which exist on the face of the globe. 

 Indeed, from the calculations which will be hereafter given 

 ( 1132), it would appear that a single cup of water may easily 

 hold a number of the smallest known species, far surpassing that 

 of the whole human population of the earth. And the ideas 

 we form of their present amount seem mean and insignificant, 

 when we contrast them with those, to which we are led by the 

 contemplation of the fossil remains of those of former epochs 

 ( 1130). 



1115. The forms presented by these Animalcules are ex- 

 tremely various. In some we can scarcely detect any definite 



FIG. 626. VARIOUS FORMS OF ANIMALCULES. 



shape ; their bodies appear composed of a mass of gelatinous 

 matter without any solid support, which may project itself into 



