1006 



SCIENCE 



[N. S. Vol. XXIX. No. 756 



Some Factors concerned in the Fixation of Nitro- 

 geti hy Azotobacter: Conbad Hoffmann and 

 B. W. Hammeb, Bacteriological Laboratories, 

 University of Wisconsin, Madison, Wis. 

 The possibility of employing azotobacter for 

 artificial soil inoculation, as well as the impor- 

 tance of its existence in soil as a nitrogen in- 

 creaser, are factors which can not be ignored. 

 With these as a basis, the work reported in the 

 paper of the above title was performed. It ap- 

 pears that some fermentable carbohydrate is 

 essential for nitrogen fixation; the same is true 

 with reference to the presence of phosphorus and 

 some base. The influence of ( 1 ) varying amounts 

 and kinds of carbohydrates; (2) of varying kinds 

 of phosphates (mono-, di and tri-forms), and 

 (3) of the period of incubation, were all factors 

 which were considered. The employment of the 

 sand slope and the large Petrie dish cultures 

 proved most eflScient in securing the maximum 

 development of azotobacter in pure culture. 

 Persistence of Anthrax Spores in Raw Water: 

 E. G. Hastings, University of Wisconsin, Madi- 

 son, Wis. 



Anthrax spores have been found to persist for 

 eight years in raw pond water. The longest period 

 of persistence in raw water noted previously was 

 five months; in sterile distilled water thirty 

 months. The water was infected by tannery refuse 

 and growth of the anthrax bacillus had taken 

 place before or after the sample was taken from 

 a stagnant pond. It would seem that the supposi- 

 tion expressed by many that the anthrax organism 

 can grow in nature is true. 



Synthetic Media for the Isolation of B. coli from 

 Water: Maurice L. Dolt, Brown University, 

 Providence, R. I. 



It was found possible to grow if. coli on one 

 per cent, solutions of asparagin if 0.2 per cent, 

 of sodium or ammonium phosphate is added. No 

 other of the soluble inorganic salts seemed to 

 serve. 



Substances having an asymmetric carbon atom 

 in their molecule and a CHOH group, such as 

 glycerin, ammonium lactate, malic acid, can be 

 substituted for the asparagin. These substances 

 seem to favor the growth of the B. coli and to 

 inhibit the growth of other water organisms. It 

 is very likely the presence of this asymmetric 

 carbon atom and the CHOH group in the cholic 

 acid of bile which gives it these same properties. 

 Every red colony developing on litmus-lactose- 

 agar made up with glycerin, ammonium lactate, 

 or malic acid in addition to ammonium or sodium 

 phosphate was a colony of B. coli. On the malic 



acid plates only red colonies developed and they 

 were all B. coli. 



The use of these media in water analysis seema 

 most promising. The presence of B, coli even in 

 small numbers can be detected by plating large 

 amounts of the water without preliminary enrich- 

 ment. 



The work is at present being extended to the 

 detection and differentiation of B. typhosus. 



The complete paper is in the Journal of In- 

 fectious Diseases, 5, 1908, p. 616. 

 A Synthetic Medium as a Substitute for Loeffler'a 



Blood Serum in the Diagnosis of Diphtheria: 



F. P. GoRHAM, Brown University, Providence, 



E. I. 



The proteid-free medium which in the liquid 

 form had been found by Hadley to be favorable 

 for the growth and toxin production of B. diph- 

 therias was used in combination with agar as a 

 substitute for Loeffler's blood serum. It was as 

 follows : 



Glycerin 3.40 parts. 



Sodium chloride 0.60 " 



Calcium chloride 0.08 " 



Magnesium sulphate 0.32 " 



Dipotassium phosphate 0.23 " 



Ammonium lactate 0.75 " 



Ferric phosphate 0.08 " 



Glycocoll O.IO " 



Distilled water to make 100 parts, 1.5 per cent, 

 agar, reaction made + 1 with sodium hydrate. 



It was found possible to make a diagnosis from 

 swabbings on this medium in less than fifteen 

 hours. 



The organisms were of about the same types 

 as on the Loeffler's blood serum, though there was 

 some indication that the granular types were 

 more common on the synthetic medium than on 

 the blood serum. 



'Note on Roup in Fowls: Philip B. Hadley, Divi- 

 sion of Biology, Rhode Island Agricultural Ex- 

 periment Station. 



The present report is based upon the examina- 

 tion of five fowls which died with the character- 

 istic symptoms of " roup." The symptoms and 

 macroscopical pathological appearances were as 

 follows: Onset of disease like simple catarrh; 

 watery exudate from nose and eyes; accumulation 

 of thick mucus or soft, cheesy exudate in orbital 

 sinus, naso-lachrymal canals and palatine space. 

 Walls of mouth cavity and anterior esophagus 

 whitened and necrotic, sometimes punctated with 

 firm, yellowish-white nodules from 1 to 12 mm. 



