442 THE BEGINNINGS OF LIFE. 



Diatoms, usually existing in stipitate clusters and which 

 go by the name of Gomphonema, has also been observed 

 by Dr. Gros ^. 



6. Resolution Into Algo'id Ccrpuscles. This change has 

 been observed to occur very frequently in small Euglense. 

 The chlorophyll corpuscles which they naturally contain 

 increase in size, and at the same time assume a very 

 bright, dark-green colour. And whilst this indivi- 

 dualization of the contents of the Euglena is going on, 

 its investing membrane gradually becomes thinner and 

 thinner, so as at last to liberate these enlarged and 

 bright-green corpuscles. They are then free to pursue 

 an independent existence. Sometimes, whilst this 

 change is taking place and when the membrane of the 

 vesicle is still intact, a number of very active Bacteria 

 may be observed distributed amongst the bright-green 

 corpuscles, although no such organisms are to be 

 seen in the fluid outside. They appear to have been 

 produced from a retrograde change taking place in 

 some portion of the matter of the Euglena which 

 had not been absorbed by the growing chlorophyll 

 corpuscles. 



The subsequent fate of such corpuscles seems to be 

 very similar to that of others which we have already 



1 Loc. cit., p. 324; PI. H, fig. 2 ; and PI. G, fig. 11. I have occa- 

 sionally seen large Naviculse densely packed within a portion of a 

 young Vaucheria filament whose ordinary contents had in this part of 

 its length wholly disappeared. See also Mr. Metcalfe Johnson's state- 

 ments concerning similar mode of origin of Diatoms from Algce, in 

 ' Monthly Microsc. Joum.,' Jan. 1870, p. 31. 



