NOVEMBEB 2, 1917] 



SCIENCE 



433 



recently published work " The Origin and 

 Evolution of Life," where it reads (p. 85) as 

 follows : 



, The great geologic antiquity even of certain 

 lower forms of bacteria which feed on nitrogen is 

 proved by the discovery, announced by Walcott in 

 1915, of a species of pre-Paleozoie iossil bacteria 

 attributed to "Micrococcus," but probably re- 

 lated rather to the existing Nitroso coccus, which 

 derives its nitrogen from ammonium salts. 



Perhaps the words " rendered probable " 

 would be more accurate than the word 

 "proved" in the sentence as it stands. 



As to the second point, Dr. Breed raises the 

 question whether the fossil markings described 

 by Dr. "Walcott in the fossil limestone are 

 actually bacteria. On this point there can be 

 no doubt whatever. Walcott reproduced for 

 comparison an illustration of Micrococcus 

 from the Encyclopedia Britannica and re- 

 ferred the Algonkian bacteria to Micrococcus 

 sp. undt = species undetermined. 



A B 



the conclusion that the Algonkian type was 

 closer to the existing Nitroso coccus, which de- 

 rives its nitrogen from ammonium salts, than 

 to Micrococcus. The similarity between the 

 Algonkian bacteria (A) and some recent forms 

 of nitrifiers (B, 0) is shown in the compari- 

 son of the parts indicated by arrows in the 

 figure. 



A comparison of these fossil and recent prep- 

 arations appears to bear out my statement, 

 made on the authority of Dr. Kligler, that 



The cell structure of the Algonkian and of the re- 

 cent Nitroso coccus bacteria is very primitive and 

 uniform in appearance, the protoplasm being 

 naked or unprotected. 



Here the word " relatively " might have been 

 inserted. 



My entire chapter on bacteria was pre- 

 pared with the kind cooperation of Dr. I. J. 

 Kligler. Walcott's discovery was cited as in- 

 dicative of the antiquity of bacteria and my 



c 



^m 



^ 



At my request this very interesting deter- 

 mination by Walcott was taken up by Dr. 

 Kligler, and after a careful investigation he 

 made the series of special preparations of bac- 

 teria which are reproduced (B-F) in the ac- 

 companying figure together with parts of Wal- 

 cott's two figures (A). Dr. Kligler came to 



statement was intended to be hypothetical and 

 not categorical. Dr. Breed may be correct in 

 the assumption that the fossil bacterial im- 

 pressions represent forms related to the denitri- 

 fying bacteria and not to the nitrogen fixers or 

 nitrifiers, as Dr. Kligler has suggested. The 

 acceptance of his view would strengthen rather 



