13 



distilled water and all liiiiips tiroken u}) with a ^lass rod. Fifty cubic 

 centimeters of water was then added to each beaker and the contents 

 stirred thoroiiiihly for fifteen minutes. After the insoluble residue 

 had l)een allowed to settle for three to five minutes, the litjuid from each 

 beaker was decanted through filters into ^50 cubic centimeter flasks. 

 The insolut)le portion was thorou<4-hly drained and then 25 cu))ic cen- 

 timeters of w ater was added. The water and residue were thorou<4hly 

 stirred for seven to eioht minutes, and, after settling, decanted upon the 

 same Hlter as before. This treatment was continued, 25 cid)ic centime- 

 ters of water beinijf used each time, until the filtrate from each portion 

 of meat measured about 230 cubic centimeters. The material on the 

 filters was allowed to drain completely after each extraction. After 

 the last extraction the entire content of each beaker was tlirown upon 

 the filter and, when drained, was washed twice with a small quantit}^ 

 of distilled water. Each ilask was rinsed twice with water, after 

 which the filtrates were coml)ined and diluted to 5 liters. 



Determination of total ftolids and a.'^h. — Portions of the filtrate of 

 100 cubic centimeters each were evaporated to dryness in weighed 

 platinum dishes. Th« residues were dried in a water oven for one hour 

 or until the weight of each was approximately constant. The dried 

 residues were ignited carefully over a free flame at a very low red heat 

 until colorless or nearly so. The ash was weighed cjuickly, reheated, 

 and again weighed. This treatment was repeated until the weight 

 was constant. 



Dtteriiihudion of total nitrogtn. — Portions of 1<M) cubic; centimeters 

 each were used to determine the nitrogen h\ the usual Kjeldahl 

 method. Dilute standard solutions (al)out one-fifteenth normal) were 

 used for this part of the work. 



DetermiTiatlon of nitrogen precipitated in the form <f coagulated 

 protelds In ncxdral solution.- — Poi'tions measuring 200 cubic centi- 

 meters were evaporated upon the water bath to a volume of about 40 

 cubic centimeters. The solution was then exactly neutralized with 

 decinormal sodium hydroxid solution, litmus paper being used as 

 indicator. The neutral solutions were w'armed upon the water bath 

 for ten minutes, then filtered at once, and the coagulated residues 

 washed thoroughly with hot water. The nitrogen in the residues was 

 determined, much care l)e'ing taken to remove all the coagulated 

 proteid from the beakers. 



Determination of nitrogen precipitated as alhiunoses hy zinc sul- 

 phate. — The filtrates and washings from the above determinations of 

 coagulable proteid were evaporated upon the water bath to a volume 

 of 30 cubic centimeters and allowed to cool. One cubic centimeter of 

 50 per cent sulphuric acid was added and the solution completely satur- 

 ated with crystallized zinc sulphate. The solution was heated upon a 

 water bath with constant stirring until perfectly clear, allowed to stand 



