THALLOGENS. 107 



13. The excessively minute and almost vapor-like 

 sporules of fungi float about in the atmosphere in count- 

 less numbers, only waiting for a fitting soil in which to 

 grow. As long as there is no refuse matter to be re- 

 moved these scavengers are unemployed, but the small- 

 est quantity of decaying animal or vegetable matter left 

 exposed becomes covered with spores, which develop 

 with astonishing rapidity. A scanty number of spores, 

 only to be detected by careful research, will in a few 

 days, and sometimes in a single night, give birth to 

 myriads, to repress or remove the nuisances referred to. 

 When the offal diminishes fewer of the spores find soil 

 on which to germinate, and when all is consumed the 

 active legions return to their latent or undeveloped 

 state. Like Milton's spirits 



So thick the aery crowd 



Swarmed and were straitened ; till, the signal given, 

 Behold a wonder ; they but now who seemed 

 In bigness to surpass earth's giant sons, 

 Now less than smallest dwarfs. 



14. In the chapter on the Protophyte type of vegeta- 

 ble life, we considered the bioplasm, or living matter, 

 differing in each kind, yet agreeing in one particular, 

 namely, that each cell exhibits a repetition of the form 

 and power of the parent-cell. In the Thallogens we find 

 another idea predominating, or rather two leading ideas, 

 the co-ordination of many cells in the structure of one 

 individual, and the differentiation of cells in form and 

 function, analogous to the division of labor in human 

 society. Respecting the first, Joseph Cook has well re- 

 marked, in his axiomatic style : " Living tissues are co- 



