1890.] NEW YORK ACADEMY OF SCIENCES. 25 



of about 700 c.c. capacity containing some spirals of platinum 

 wire; 25 c.c. of potassium sulphide solution (containing 40gms. 

 per litre) are then added. The Erlenmeyer flask is fitted with a 

 Wiirtz tube, and this in turn connects with a common block-tin 

 condenser. To the drip end of the condenser is attached a tube 

 bearing a bulb. The other end of this bulb tube dips under the 

 surface of the liquid in the receiving flask. This flask should 

 contain the standard acid in amount from 85 to 50 c.c, as the 

 case demands. I prefer to use normal hydrochloric acid, but*| 

 sulphuric acid may be used. 



Just before starting the distillation, from 50 to 100 c.c. of 

 caustic soda (27 per cent) are cautiously run into the distilling 

 flask and mixed with the contents, avoiding violent agitation. 

 A piece of red litmus paper is now dropped in the flask, which 

 is immediately stoppered. The litmus paper serves to show 

 whether enough alkali has been added; if not, measure out 

 10 c.c. more, uncork the flask, and introduce as before. Con- 

 tinue these additions until the contents are alkaline; but avoid 

 a large excess. When ready, heat up slowly to boiling, and keep 

 up the distillation until at least 150 c.c. of distillate have passed 

 over. Remove the receiving flask, and determine the acidity of 

 the contents with j- ammonia or -^ potassium hydrate, using 

 methyl orange as indicator. 



A blank test should be made with the reagents, and under 

 the same conditions as the original. Time of operation, two to 

 two and one-half hours. 



Calculation of Results. — The number of cubic centimetres 

 of acid neutralized by the distillate, calculated to nitrogen and 

 multiplied by 6.25, is equivalent to the albumenoids, i.e., glu- 

 ten, etc. 



The determination of starch by tlie ordinary methods hitherto 

 in vogue is uncertain and tedious. I refer to inversion followed by 

 use of Fehling solution and O'Sullivan's diastase method. The 

 first is unreliable, there being no certain method of ascertaining 

 when all the starch has been converted into glucose; or the pro- 

 cess may go too far, decomposing the starch to hnmic acid, etc.; 

 result, low figures in both cases. 



The second is a more reliable method, but there is great difii- 

 culty in preparing the diastase, which does not keep. That pur- 

 chased from dealers cannot be used. 



Von Ashoth Process. 



This depends on the fact that starch unites with barium oxide 

 to form a compound containing 19 per cent of barium oxide. 



