RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



The physical chemistry of the proteins, T. B. Robektson {New York and 

 London: Longmans, Green & Co., 1918, pp. XV+J/83, figs. 7). — This is a new 

 edition in English of the book previously noted (E. S. R., 29, p. 408), and has 

 been almost entirely rewritten and enlarged to include the literature on the 

 subject through the middle of 1917. 



In the introduction the aiithor comments upon the development of two rather 

 sharply differentiated schools of opinion in regard to proteins and colloids in 

 general. " The one school endeavors, so far as technical difficulties permit, to 

 apply directly, with modifications suggested by the properties and structure of 

 the particular colloid under investigation, the known laws of what may be 

 termed ' molecular ' physical chemistry to protein and other colloidal systems, 

 while the other school hesitates to^lo so." The author claims allegiance to the 

 former school, and in this work endeavors to interpret tlie physico-chemical 

 behavior of the proteins in the light of the laws of Boyle and Gay-Lussac as 

 applied to solutions by van't Hoff and of the Guldberg and Waage mass-law. 

 He has assumed the validity in protein systems of the first and second laws of 

 heat, and in considering the electrochemical behavior of proteins the applica- 

 bility of Arrhenius' hypothesis of electrolytic dissociation, of Kolrausch's law 

 of the independent motion of ions, of the Nernst theory of concentration cells, 

 and the applicability of the Guldberg and Waage mass-law to reactions between 

 ions. 



The book contains an extensive bibliography and an appendix in which the 

 author's technique of electrochemical measurements in protein systems is 

 explained. 



A detailed method for the preparation of histidin, H. M. Jones {Jour. Dial. 

 GJiem., 33 {1918), No. 3, pp. 429-^31). — The author describes in detail a method 

 for the preparation of histidin from the so-called " blood paste," a concentrated 

 suspension of red blood corpuscles obtained by centrifugating defibrinated ox 

 blood. The method is a more detailed statement of the one already in use and 

 emphasizes certain apparently insignificant steps in the process which are 

 easily overlooked. 



The distillation of cellulose and starch in vacuo, A. Pictet and J. SABASii!^ 

 {Compt. Rend. Acad. Sci. [Paris], 166 {1918), No. 1, pp. 38, 39).— The distilla- 

 tion of cellulose under a pressure of 12 to 15 mm. results in the formation at a 

 temperature of between 200 to 300° C. of a thick yellow oil which soon changes 

 to a pasty semicrystalline mass. Purification by recrystallization from boiling 

 acetone or water gives a white anhydrous crystalline substance very soluble in 

 water, alcohol, acetone, and acetic acid, and almost insoluble in other organic 

 solvents. The water solution is neutral to litmus and both sweet and bitter to 

 the taste. It does not distill without decomposition at ordinary pressure. It 

 reacts readily with acetyl and benzoyl chlorids, giving triacetyl and tribenzoyl 

 derivatives. 

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