19201 FIELD CROPS. 635 



brown pigments in media containing proteins and amino acids, tlie production 

 ^f a brown pigment being due, in most cases, not to a tyrosinase reaction. 

 Only some strains of Actinomyces fscdbics and a few other chromogenus species 

 were able to proiiuce a soluble brown pigment from tyrosin ; most of the species 

 that produced brown piirments on protein media, even if tliey did not give tlie 

 tyrosinase reaction, produced an oxidase. 



"For comparative cultural purposes a definite incubation period is very 

 important, since two oiganisms will show a different relationship in their 

 metaboli.sm (splitting of nulk in this case) at different periods of incubation. 

 With the prolongation of the period of incubation the difference in the quantity 

 of the products obtained from the splitting of milk will greatly decrease and 

 may, in some cases, almost disappear." 



Studies in the metabolism of actinoniycetes. — IV, Changes in reaction as 

 a result of the growth of actinoniycetes upon culture media, S. A. Waksm.\n' 

 and J. S. JoFFE {Jour, liact., 5 (1920), No. 1, pp. 31-Jf8). — Investigations con- 

 ducted at the New Jersey Experiment Stations are reported, which dealt with 

 the changes in reaction of the culture medium as affected by the growth of 

 actinoniycetes, as w'eli as the effect of the initial reaction of the medium upon 

 the growth of these soil organisms. 



It was found that the actinoniycetes are not able to produce any appreciable 

 quantities of acid from the carbohydrates studied, the changes in the reaction 

 of the medium being due to the source of nitrogen. With different sources of 

 carbon and .sodium nitrate as a source of nitrogen, the reaction of the medium 

 tended to become alkaline. When sodium nitrate was replaced by sodium 

 nitrite those organisms that were able to grow on the latter source of nitrogen 

 changed the reaction of the medium to acid rather than to alkaline. When 

 ammonium salts of strong acids were present as the only source of nitrogen, the 

 medium tended to become distinctly acid, due to the fact that the cation was 

 used up by the organism and the anion was left in the medium. W'ith proteins 

 and amino acids it was found that the reaction may be unchanged or may 

 become acid or alkaline, depending on the species, source of carbon, and 

 original hydrogen-ion concentration of the medium. Certain species seemed to 

 change the reaction of the protein and amino acid media always to aikaline, 

 others always to acid. Leucin as the only source of nitrogen nearly always 

 favored a distinct acidity of the medium. The presence of an available 

 carbohydrate in a protein medium seemed to favor an acid reaction. W^ith 

 media of different hydrogen-ion concentrations the reaction tended to an 

 optimum ; the more acid media tended to become less acid and the more alkaline 

 media above the optimum less alkaline. 



Plant hygiene, G. C. GouGH (Gard. Citron., 3. ser., 67 {1920), Nos. 1126, 

 pp. .'fO, Jfl; 1727, p. 5ff). — Illustrative matter on plant hygiene is cited as fur- 

 nished by several investigators. 



Inventory of seeds and plants imported by the Office of Foreign Seed and 

 riant Introduction during the period from April 1 to June .30, 19 16 

 {U. .S'. Dcpt. A(/r., Bur. I'Utnt Indus. Inventory No. J,7 {1920). pp. 96, pis. 5).— 

 Notes are given on about 600 lots of seeds and plants imported for trial in this 

 country. 



FIELD CROPS. 



[Report of field crops work in Louisiana, 1910], .\. F. Kiddkr, W. G. 

 Tag(;\i:t, and G. D. Cain {Louisiana Stas. Rpt. 1919, pp. If/, 15, 22, 23, 31-3/f). — 

 This continues work previously noted (E. S. K., 39, p. 528). 



In experiments at Baton Rouge yields indicated that velvet beans planted 

 in the row with com produced more than when planted in every other row or 



