110 THE AMERICAN NATURALIST [Vol. LVI 



certain factors of the environment. It seems inconceiv- 

 able to me that the great diversity and complexity of 

 functional nature in the bacteria could have arisen other- 

 wise. Nevertheless, analogies between phenomena in 

 animate and inanimate nature must not be pushed too 

 far in the absence of the necessary facts for their sup- 

 port. While I believe them to be of great significance, I 

 do not desire to be dogmatic on the subject in the slightest 

 degree. 



While all the foregoing as regards the evidence for 

 orthogenesis may be accepted as true, it does not follow 

 that the doctrine of orthogenesis is anything new or sig- 

 nificant or was so when it was first enunciated. It seems 

 to me to constitute merely one way of describing the 

 actual condition of progressive series in evolution, but 

 it seems to me that it explains nothing. In so far, how- 

 ever, as its advocates espouse the cause of those who be- 

 lieve in and give evidence for the inheritance of acquired 

 characteristics, the potency of environment in inducing 

 fundamental and permanent changes in the organism, and 

 the theory of mutation, they do contribute something sig- 

 nificant to the discussions and experiments which consti- 

 tute the amorphous symplasm, metaphorically speaking, 

 from which our knowledge of the well-defined and real 

 nature and origin of life may some day be expected to 

 emerge. 



It is, perhaps, of particular importance now to con- 

 sider the bacteria as a class and their probable origin as 

 bearing on the question for which we are trying to find 

 an answer. There is a general disposition, and i)articu- 

 larly is it true that there has been in the past, on the 

 part of biologists and natural philosoph('r>, so called, to 

 l)lace the bacteria in point of origin anioiii;' the most 

 primitive of living organisms. There is hiticIi indinal ion, 

 indeed, to regard them as the most priiiiitixc oruanisnis. 

 While, superficially, this view seems attractive and cor- 

 rect, it loses much of its cogency when one takes into 

 consideration the following situation: In all 1;ut a few 



