June 14, 1918] 



SCIENCE 



589 



and Liitken, Steindachner ; C. pentadaciylus 

 Peters; C. mystacinus Bunneister; C. podi- 

 cipinus Cope, etc. Generic names ending in 

 gnathus are as rare among birds as those end- 

 ing in ryhnchus and ramphus are common 

 (and needless to say no ornithologist, or other 

 zoologist, has used the latter as neuters), but 

 we have at least Hemignathus which they have 

 accepted as masculine without exception, 

 among them the purist of purists. Dr. J. 

 Cabanis who is responsible for Hemignathus 

 procerus. Finally, giving a few examples from 

 the fishes, I quote Hybognathus accepted as 

 masculine by Girard, Jordan and Gilbert, 

 Cochlognathus by the same authorities, and 

 last but not least Syngnathus proposed as a 

 masculine by Linna>us himself and so accepted 

 by all subsequent ichthyologists. In fact, it 

 is probably not too risky to say that not imtil 

 Cope discovered that the unmutated gnathos 

 is feminine (reversing his own previous prac- 

 tise), were any of the mutated composites 

 treated as feminine. It is also safe to say that 

 most of the illustrious men who adhered to the 

 masculine gender, when so indicated by the 

 original proposer of the name, knew what they 

 were about and showed proper " respect to the 

 Greek language." 



Leonhard Stejneger 



evolution of bacteria 



I W.4S greatly interested in Professor Bu- 

 chanan's article in Science^ entitled " The 

 Evolution of Bacteria." It is not my inten- 

 tion at the present time to take up at length 

 those points raised by him which are admit- 

 tedly matters of opinion. In matters of clas- 

 sification, there are many possible interpreta- 

 tions of available facts, which can not be 

 easily proved or disproved. The conclusions 

 reached were based on the facts at hand, 

 though it was admitted at the outset that the 

 facts were inadequate. The final answer to 

 these questions can not be obtained at the 

 desk, but in the laboratory. Most of the ques- 

 tions concerning bacterial relationship and de- 

 scent can be tested experimentally by a study 

 of their metabolic and antigenic characters, 



1 Science, 1918, N. S., XLIII., 320. 



and it is such investigations that my article 

 was intended to stimulate. 



Dr. Buchanan did, however, raise certain 

 questions of fact which require some com- 

 ment. In my argument in favor of the prim- 

 itive character of bacteria the unique combi- 

 nation of the ability to subsist on simple in- 

 organic compounds plus an extreme sensitive- 

 ness to sunlight, which excluded aid from that 

 source, was advanced. This combination does 

 not obtain in either plant or animal cells. 

 Cells so constituted as to live on simple in- 

 organic compounds without the aid of an ex- 

 ternal source of energy may, it seems to me, 

 reasonably be considered as primitive. The 

 sulphur bacteria, mentioned by Dr. Buchanan, 

 contain a pigment which protects them from 

 sunlight and which according to Englemann 

 apparently functions somewhat like the chloro- 

 phyl in plants. Molisch dissents from Engel- 

 mann's view but claims that these bacteria must 

 have organic food for their nutrition. Why 

 they should be considered more primitive than 

 the prototrophic bacteria is, therefore, not al- 

 together clear. 



In regard to the source of the volatile acids 

 and alcohols for bacterial nutrition, I might 

 refer to Kaserer's^ rejwrt of nitrifying bacilli 

 which convert (NH^),C03 to formic acid and 

 free N, or nitrates. These compounds are 

 not, therefore, necessarily the product of car- 

 bohydrate fermentation. 



The author draws the inference that by 

 utilization of C0„ I had in mind oxidation. 

 It requires no profound knowledge of chemistry 

 to realize that such a thing is not possible. 

 What was implied throughout was an ability 

 on the part of the cell to assimilate CO,. In- 

 stances of such assimilation are numerous and 

 this power is particularly evident among the 

 nitrogen-fixing bacteria, the energy apparently 

 being obtained from the oxidation of the N 

 with a simultaneous reduction of the CO,. 



Reports of prototrophic denitrifying bac- 

 teria arc admittedly not " common and well 

 known." They have, however, been described 

 by Hiltner and Stromer.' Somewhat more 



2 Cent. f. Bakt., II. AM., 1908, XX., 401. 



3 Bef. Bot., 1904, XCV, 157. 



