AGRICULTURAL CHEMISTRY — AGROTECHNY. 11 



Progress made in regard to the fermentation organisms and enzyms, A. 

 Koch (Jahresber. Gdrungs-Organ., 20 (1909), pp. VII I +659). —This is a ret- 

 rospect of the work published during 1909, including text-books, etc., (pp. 

 1-17) ; methods and apparatus (pp. 18-47) ; morphology of yeasts and bacteria 

 (pp. 48-84) ; general physiology of bacteria (pp. 85-188) ; special kinds of fer- 

 mentations such as alcoholic, lactic acid, and those in cheese and milk ; utiliza- 

 tion of atmospheric nitrogen, nitrification, etc. (pp. 189-487) ; and enzyms 

 (pp. 48.8-030). 



In regard to the ferment nature of peroxidase, A. Hesse and W. D. 

 KooPER (Ztschr. Untersuch. Nahr. u. Oenussmtl., 24 {1912), No.5, pp. 301-309).—- 

 A discussion of Grimmer's statements in regard to peroxidase (E. S. R., 27, p. 

 803) is followed by the results of some experiments relative to tlie nature of 

 peroxidase in milk. 



It is shown that the reaction, when brought into contact with certain reagents, 

 e. g., Rothenfusser's, Storch's, or Arnold's, in the presence of hydrogen peroxid, 

 is due to the catalytic action of iron compounds present in milk. A solution 

 containing less iron (0.004 per cent) than reprecipitated albumin contains pro- 

 duced a marked reaction with Arnold's and Rothenfusser's reagents. 



The reason that milk loses its activity after being boiled is the denaturizing of 

 the compounds giving the peroxidase reaction. Lactic acid, sodium thiosulphate, 

 and ethyl, methyl, and amyl alcohols destroy or inhibit the appearance of the 

 peroxidase reaction in milk. The same inhibition was noted when the various 

 chemical substances were added to a solution of iron lactate, which, under 

 ordinary conditions in the presence of hydrogen peroxid will give the same 

 reaction as milk. 



Mercuric chlorid and chloroform, two pronounced enzym poisons, do not visibly 

 affect the appearance of the reactions in either the iron solution or milk. 

 Rothenfusser's reaction can be stimulated to greater intensity by other sub- 

 stances present in milk, such as alkali phosphates, carbonates, and citrates. 

 Theso- alkaline substances are inactivated by boiling. 



Cleavage of a- and j3-methyl glucosid by Aspergillus niger, A. W. Dox 

 and R. E. Neidig (Biochem. Ztschr., 46 {1912), No. 6, pp. 397-402, fig. i).— In the 

 experiments 8 species (A. niger, A. clavatus, A. fumigatus, PcniciJHum camem- 

 herti, P. expansum, P. chrysogenum. P. roqiieforti, and P. digitaturn) were 

 cultivated in a solution consisting of 0.5 gm. magnesium sulphate, 1 gm. sodium 

 phosphate, 0.5 gm. potassium chlorid, 2 gm. ammonium nitrate, and 0.01 gm. 

 ferrous sulphate in 1,000 cc. of water for the purpose of studying the effect of 

 a- and jS-methj'l glucosids upon the intensity of the growth. There was ap- 

 proximately 2 per cent of the methyl glucosids present. The fungi grew much 

 better in the j3-methyl glucosid than in the a form. 



A. niger acts only slightly on the j8 form, and practically not at all on the 

 a-methyl glucosid. Yeast, on the other hand, acts only on the a form. 



Determination of alkalis in silicates by decomposition with calcium 

 chlorid, E. Makinen {Bui. Com. Geol. Finlande, 1911, A'o. 26. pp. 8). — The 

 method suggested is as follows : Five gm. of the finely powdered silicate, and 

 the greatest part of 5 gm. of dry calcium chlorid is mixed and placed in a 

 platinum crucible (of such a size that the mixture will not fill more than two- 

 thirds of the vessel) ; the remainder of the calcium chlorid is spread over the 

 mixture, and the crucible heated with a slight flame for from 5 to 10 minutes 

 in order to dry the moist calcium chlorid. The flame is then gently raised until 

 all of the calcium chlorid is melted, after which it can be raised to any height 

 without any danger of the mixture spurting. The heating is continued until 

 the melt begins to solidify, which requires about one-half hour. After cooling, 

 the mass Is treated according to the J. Lawrence Smith method, that Is, It is 



