AGRICULTURAL CHEMISTRY. 911 



tli(> ;ini(iunr of wator and hydrooliloric acid absorbed by casein during artificial 

 pcptit- dijiestiiin. 'i'lic increase in wcit^lit was divided irre^'niarly between the 

 water and bydroililnijc acid. 



On the hydrolytic cleavage products of caseoplasteins, L. Rosenfeld 

 {BcHr. Vhciii. I'hi/siul. II. I'olli., !) {11107), \o. '>-7. />/>. 215-231).— So-caUed 

 plasteins were prepared from casein by digesting; the casein with pepsin and 

 iiydrochloric acid, neutral izinji with sodium hydro.xid, evaporating until the 

 content of solids was about :iO per cent, acidifying with hydrochloric acid, 

 and adding rennet, the resulting precipitate being designated plastein. The 

 ])roperties of ."> preparations of this kind were studied in comparison with 

 casein. The plasteins showed a higher percentage of carbon and a lower 

 percentage of nitrogen. The idiiowing cleavage products were obtained fi-om 

 the plasteins: Arginin, hislidin. lysin, tyrosin, leucin, a-i»yrrolidin carbonic 

 acid, pheuylalanin, and glutaniinic acid. As compared with casein the i>Iastein 

 sliowed a much lower pi'rcentage of amids. 



Disadvantages of potassium bichromate for the lareservation of milk 

 samples for analytical purposes, 1'. (^kelot {Join: J'hanii. ct Vhim., 6. ser., 

 2.j {IDOl). Xo. 8. lip. .'jiiH-.n.i). — Various objecticms to the use of potassium 

 l)ichromate are discussed. The most serious of these, according to the author, 

 is the fact that potassium bichromate even in the proportion of 2:1,000 and 

 without the addition of sulphuric ;icid produces in uiili< a substance giving the 

 general reactions of aldehydes. whi<-h may easily lead to an error as regards 

 the use of formaldehyde as a preservative. 



The chemistry of Hehner's test for formaldehyde in milk, O. Rosenheim 

 (Aiiiilyst, 32 {1901). A o. .>'7,;, //p. U)G-108). — Pure sulphuric acid and pure 

 formaldehyde give no color reaction with proteins. A color is, however, ob- 

 tained after the addition of small amounts of oxidizing substances. The author 

 does not believe that this color is due to the interaction of the oxidation 

 products of protein with formaldehyde. He obtained evidence, however, to 

 show that the formaldehyde may first be oxidized, giving rise +o an intei"- 

 mediate oxidation product which reacts with the protein, and also that the 

 fonnaldehyde may first combine with the ]irotein forming an aldehyde protein 

 compound which subsecpiently becomes oxidized. The formaldehyde reaction, 

 which is a general one for proteins, depends upon the presence of the trypto- 

 phane group in the protein molecule. 



The cherry-red coloration of milk in the jDresence of concentrated alkalis, 

 C. Gautier, a. Morel, and O. Monou {('ompt. Rend. Hoc. Biol. [Pnri.'i], 62 

 {1907), A'o. 11, pp. 5.'i2, 5.'i3). — Tests are reported to show that the red color 

 lu-oduced in milk i)y the addition of one-fifth its volume of 40 per cent potas- 

 sium or sodium hydroxid is due solely to the simultaneous presence of a proteid 

 and a carbohydrate, which is contrary to the view^ recently expressed by Kriiger 

 (E. S. R., 18, p. 810). The reaction of glycocoll with lactose and maltose was 

 so marked that the authors believe that glycocoll may be used for the detection 

 of these two sugars. 



A comparison and criticism of the methods for the detection and 

 estimation of cocoanut oil in butter, T. R. IIougso.n {Vhcm. Xeirs, 95 {1907), 

 \o. 2'it!s. pp. 121. 122). — The author concludes that "the saponification number 

 is of no practical value, either (iualitativ(>ly or (juantitatively. The Reichert- 

 Wollny number may show some indication of the presence of cocoanut oil if 

 the amount present in the sample is large. Wijsmann and Reijst's method 

 IE. S. R., 17, p. 8.''>41 is by far the best (jualitative experiment, since it shows a 

 difference between the 2 silver numbers in the presence of even as little as 5 



