AGRICULTURAL. CHEMISTRY — AGROTECHNY. 203 



author, the catalase is probably of bacterial origin. It may be completely de- 

 stroyed or weakened by the addition of various presen'atives. 



For reductase it was noted that the greater portion goes over into the cream 

 when centrifugally separated, but that when separated by hand very much less 

 passes over into the cream. Reductase multiplies more rapidly in skim milk 

 than it does in whole milk, and according to this, this substrat in all probability 

 is the best one to use when searching for reductase. The intensity of its action 

 begins to rise until the acidity reaches 35° to 40°, then Ijogins to fall, and later 

 on begins to rise again. Its behavior toward antiseptics is the same as that of 

 catalase. As the reductase increases to quite an extent when raw milk is added 

 to boiled, the author concludes that it also is of bacterial origin. 



Oxidase goes over into the skim milk irres])ective of whether the creaming is 

 done by the centrifuge or by hand, and when the milk becomes older no increase 

 is noted. When the acidity degree rises to from 40 to 50 the blue color obtained 

 with paraphenylendiamin begins to grow paler and diminishes until no reaction 

 is obtained. This enzym (?) is not destroyed by a dose of corrosive sublimate 

 which is lethal for fermentation organisms, and contrary to the findings with 

 catalase and reductase indirect oxidase does not multiply when raw milk is 

 added to boiled milk. According to this, the enzym is not of bacterial origin. 



The author finally states that, although the test may be of value for food 

 chemists and veterinarians, he doubts whether it will ever find a general intro- 

 duction in the practical dairy industry. 



The chemistry of honey formation, M. KiJSTKNMAcnER (Bincliem. Ztschr., 

 30 {19 JO), No. 3-.'i, pp. .Ii7-2.j.',. pi. 1, fig. i).— After discussing the anatomy and 

 physiology of the honeybee, the author details the chemistry involved in the 

 transfornintion of nectar into honey. 



In regard to the determination of nitrogen by the Kjeldahl method, A. C, 

 Andersen {Skand. Arch. Phiffiol., 25 {1911), No. 1-3, pp. 96-1 Off). —Whon de- 

 termining nitrogen in platinic sal ammoniac with the Kjeldahl method the 

 author observed that a groat loss of nitrogen takes place. Some further experi- 

 ments made with milk, blood serum, and fresh egg albumin showed that when 

 using platinum as a catalyzer fairly good results could be obtained, while with 

 urine, milk treated with pepsin or trypsin, old egg white, and hydrolyzed casein 

 a large loss took place. 



The author therefore does not recommend the use of platinic chlorid as a 

 catalyzer in the method. He also points out that the formol titration method 

 does not offer any advantages in point of time or exactness over the usual 

 Kjeldahl distillation and titration method. 



Estimation of total nitrogen by means of the formaldehyde titration 

 method, L. de Jageb {Ztschr. Physiol. Chcm., 61 {1910), No. 1, pp. 1-7; nds. in 

 Analyst, 35 {1910), No. J, 16, pp. ^87, 488).— The substance is digested with sul- 

 phuric acid, as in the Kjeldahl process, and the ammonia formed is titrated in 

 the presence of formaldehyde. The method as applied to urine is as follows : 



" Phosphates are first removed by treating 40 cc. of the urine with 5 gm. of 

 sodium acetate and an excess of 10 per cent ferric chlorid solution. The mix- 

 ture is diluted to a volume of 50 cc, weighed, boiled, water added to correct for 

 loss by evaporation, and the precipitate is removed by filtration. Ten cc. of the 

 filtrate are now digested with 8 cc. of sulphuric acid and 0.5 gm. of copper sul- 

 phate, and the copper is subsequently removed as sulphid by the addition of 10 

 cc. of 10 per cent sodium sulphid solution, the excess of hydrogen sulphid being 

 boiled off. The copper sulphid is collected on a filter, washed, and the filtrate is 

 diluted to a volume of 100 cc. Fifty cc. of this solution (corresponding to 4 cc. 

 of urine) are now neutralized with sodium hydroxid solution, using phenolphtha- 



