July 9, 1915] 



SCIENCE 



71 



the amino-acid content of the mixed proteins ex- 

 pressed in per cent, of the f eedingstuff varies quite 

 markedly. 

 E. iS. Potter and R. S. Snydek: Nitrogen Distri- 



iution According to the Van SlyJce Method in 



Soils and their Sumic Acids. 



E. S. Potter and E. S. Snyder: Amino Acid Ni- 

 trogen in Soils Variously Treated. 



Mas Kahn: A Study of Urinary Mucin. 

 Max Kahn and F. G. Goodridge: On Cystine. 



F. G. GooDKiDGE: Biochemical Studies of Mercap- 

 tan. 



Max Kahn and Francis Huber: Metabolism 

 Studies of Multiple Myeloma with Bence-Jones 

 Albumose. 



Max E>hn and S. Schneidee: Study of the Min- 

 eral Metabolism of Diabetics. 



A. F. Hess and Max Kahn: Mineral Metabolism 

 of Two Cases of SemopMlia. 



Jacob Eosenbloom: A Study of the Ethereal Sul- 

 fates of the Urine in Various Diseases. 



Jacob Eosenbloom: A Modification of Gerhardt's 

 Test for Diacetie Acid. 



Jacob Eosenbloom: The Infl.uence of Low and 

 High Protein Intake on the Excretion of Ace- 

 tone, Diacetie Acid, and Beta-oxybutyric Acid 

 in Diabetes. 



William Mansj-ield Clark: On the So-called 

 " Beaction" of Bacteriological Culture Media. 

 By means of titration curves in which the quan- 

 tity of acid or alkali added to a medium is plotted 



against the resulting hydrogen ion concentration 



it is shown that: 



I. There can be no true "end point" with 

 phenolphthalein in the titration of culture media. 



II. The amount of alkali which must be added 

 in order to reach an arbitrary tiat of phenolph- 

 thalein is a function of the buffer effect of any 

 particular medium. 



III. The so-called correction of the reaction by 

 the addition of a fraction of the amount of alkali 

 required to reach an arbitrary tint of an indicator 

 may result in very different hydrogen ion concen- 

 trations in different media. 



The practise of titrating media while hot is 

 shown to give no precise data in regard to the re- 

 action of a cold medium. 



The fallacies of the titrimetric method of ad- 

 justing the reaction of culture media are summed 

 up and it is concluded that the colorimetric method 

 of adjusting to a desired hydrogen ion concentra- 

 tion is more logical. 



William Mansfield Clark: The Final Hydrogen 

 Ion Concentrations of Cultures of B. Coli. 

 The conclusion of Michaelis and Marcora that 

 the fermentation of sugars by B. coli is limited by 

 a definite hydrogen ion concentration rather than 

 by the molecular concentration of the acid pro- 

 duced was confirmed in its essentials by studies 

 with seventeen organisms cultivated in thirty dif- 

 ferent media. There were, however, minor but 

 noteworthy differences in the final hydrogen ion 

 concentrations attained in different media. These 

 differences were related to the magnitude of the 

 "buffer effect" of the different media. 



It is pointed out that the determination of the 

 final hydrogen ion concentration furnishes com- 

 parable data where the determination of titratable 

 acidity can not. 



E. H. Walters and Wm. M. Clark: The Relation 

 between the Propionic Bacteria and Eye Forma- 

 tion in Emmental Cheese. 



A careful study of pure active cultures of Ba- 

 cillus propionici isolated from emmental cheese 

 has shown that the Fitz equation 



SCsHeOar^ 2C3HeO, -f aH,0, -f CO, + H,0 

 lactic propionic acetic 



represents the relation of the end products in a 

 pure fermentation of lactic acid. Experiments 

 are described in detail which show that the car- 

 bon dioxide produced in a fermentation of this 

 kind is entirely inadequate to explain the forma- 

 tion of eyes in emmental cheese as proposed by 

 Freudenreieh and Jensen since the amount of car- 

 bon dioxide produced in cheese is greatly in excess 

 of the amount which could be accounted for in this 

 way. 



S. L. JoDiw: On the Factor to be Used for the 

 Calculation of the Phosphoric Acid in Neu- 

 mann's Method. 



S. L. JODiDi and E. H. Kjellogg: On the Factor to 

 be Used for the Calculation of Phosphoric Acid 

 in Neumann's Method. I. The Factor as In- 

 fluenced by the Water Used for Washing the 

 Yellow Precipitate. 



Egbert E. Swain and E. E. Harding: The Quan- 

 titative Estimation of Alantoin. 

 Lewis Knudson : The Influence of Certain Sugars 

 on the Growth and Respiration of Vetch. 

 An extensive investigation has been made on 

 the direct absorption of various sugars by vetch 

 {Vicia villosa). Plants were grown for the most 

 part on agar nutrient media in large cylinders 

 under sterile conditions. The results indicate that 

 vetch is able to absorb and utilize saccharose, glu- 



