THE BEGINNINGS OF LIFE. i6l 



midiae. Nageli ("Einzell. Alg.") arranges them with 

 the Palmellse as a distinct group, and in this has the 

 support of Braun ("Gen. Nova," p. 69).' In a later 

 portion (p. 752) of the work he says:— ^ So far as we 

 can judge, it is not yet determined whether they should 

 remain united with the Palmellacex to which they have 

 been referred by Nageli, or, with some few other Algae, 

 form a distinct group near Palmellaceae, and perhaps 

 Volvocineas. They cannot, we think, continue to be 

 considered as belonging to the Desmidiacese/ All 

 these discrepancies of opinion are not difficult to 

 understand if we bear in mind the absence of any 

 real grounds for distinguishing the several forms, and 

 at the same time consider the difficulties of the old 

 systematic writers who, in accordance with their theo- 

 retical notions, felt bound to conceive that specific, 

 generic, and family distinctions existed — even though 

 observation taught them that the several forms were 

 related to one another in much the same way as the 

 different patterns observable in a kaleidoscope. Now 

 experiment comes in to demonstrate the fundamental 

 kinship which exists between the several forms. 



Let the reader compare the representations of the 

 organisms which have been found an the twenty-four 

 experiments in which the flasks were heated to tempe- 

 ratures ranging from 290 — 307° F, and he will then 

 perceive that, so far as we have gone, the views enun- 

 ciated in the present chapter (founded in part upon the 



VOL. II. M 



