RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHFT. 



Contributions to t .e study of maize deterioration, C. L. AiSBERG and O. P. 

 Black (U. 8. Dept. Agr., Bur. Plant Indus. Bui. 270, pp. 48, pL 1). — Tlie re- 

 sults of this investigation, continuing previous work (E. S. R., 24, p. 409) 

 furnish additional data for explaining the discrepancies in the various bio- 

 chemical investigations of molds reported. It is maintained that previous in- 

 vestigators have failed to realize that the nature of the metabolic products 

 varies with the species studied, with the reaction of the culture medium, with 

 the amount of aeration given, and possibly with the nature of the nitrogen 

 furnished as a food, supply. 



In this work 6 species of maize were studied, of which 2 were capable of 

 elaborating substances which were toxic to mice. Two of these species, one 

 toxic and the other nontoxic, were studied in detail. " The first, identified as 

 PenicilUum puberulum, elaborates a toxic product which was isolated and for 

 which the name ' penicillic acid ' and the formula CsHio04 are suggested. [It is 

 not considered the substance isolated by Gosio, but probably related.] This 

 substance behaves like a monobasic acid. It is toxic to animals when injected 

 subcutaneously, causing death in a dosage of about 0.2 to 0.3 gm. per kilogram 

 of body weight. The formation of i>enicillic acid is more abundant when the 

 air supply is limited and the reaction of the medium is acid. The form in which 

 nitrogen was offered the fungus seems also to have some influence on its forma- 

 tion." 



A substance partly crystalline and partly oUy, with a cresol-like odor, was 

 noted among the metabolic products, Penicillic acid has some antiseptic prop- 

 erties. 



" P. puberultttn was always found to produce alcohol when grown in the pres- 

 ence of sugar. Old cultures contain minute amounts of oxalic acid. In the 

 presence of sugar and leucin no amyl alcohol is produced, although Icucin is 

 consumed. A small quantity of volatile acid, however, is formed. In the pres- 

 ence of sugar and tyrosin neither tyrol nor tyrosol is produced, though tyrosin 

 is consumed. A small quantity of volatile acid is formed. 



" Both the culture fluid and the mycelium were examined for oxidizing 

 enzyms. The former contains an abundance of catalase, though no oxidase 

 detectable by guaiac, aloin, or benzidin. A very faint peroxidase reaction was 

 found, due perhaps to the presence of chlorids. The statement of Loe\^ [E. S. 

 R., 13, p. 115] that filtered P. glaucum cultures contaiu only catalase is there- 

 fore amply confirmed." 



The mycelium was tested for oxidizing power by the method of oxygen ab- 

 sorption developed by Bunzel (E. S. R., 27. p. 9). Oxygen absorption was 

 observed only when the mold was grown on Raulin's medium with an addition 

 of 5 per cent of a mixture of 2 parts Na2HP04 and 1 part NaHjPO^. 



" The second organism, P. stoloniferuni, was nontoxic. Unlike the other 5 

 studied, it was isolated from Italian maize. It elaborates a new phenolic acid, 

 95099°— No. 1—13 2 7 



