4'*. J Idler's ;-/;;./ test. I 'lace a half inch of strong nitric 

 1 in a tc-t-tuhc. 1'oiir UIM)II thi>. allowing it to run gently down 

 thf -iik- Hi the tul'e. a little "f the weak alhuniin solution. -Vote 

 the \\hite cloud at the junction of the t\vu -ub-tances ; this is Hel- 

 ler'- tc-t f->r alhuniin. It U u-ed to te>t the presence <>f alhuniin 

 in the urine. 



I ). I >i \i I 'KOI i.i N 



A. !! an e|ual volume of m', XaCl solution to some 

 undiluted white of egg and place in a collodion or parchment 

 paper bag. or animal numhrane. I 'lace the bag in a jar of water 

 in such a way that only the lower part (covered hy the membrane) 

 is in contact with the di-tilled water. After two hours, observe 

 whether any considerable amount of the albumin has passed through 

 the membrane. I Mermine whether any has passed through lu- 

 te-ting the water in the jar by one or two of these tests given above. 

 Ma- Xal'l pa--ed through? Te-t with _" , AgX<>. solution. 



\< I lo\ o|." M.CTK AL SALTS. "SALT1NC, OCT." 



51. Add Xal'l crystals to a solution of egg white to saturation. 

 Am precipitation? Niter and test the filtrate for protein. Is 

 precipitation complete? Test the residue on the filter for protein. 



oti- the similarity to the salting out of snap by XaCl. 



.-_. kepcat K\p. 51. u-ing powdered ( XI 1, )._.S< ), cry-tals instead 

 of Xal'l. \\hich -alt i- more effective a- a precipitant? Kgg albu- 

 men i- purified by repeated -alting out with iXII,i.S<> 4 , which 

 pucipitate- completely tin 1 protein. 



At I Io\ i ,| \ ( ||is AM) ALKALIKS. 



5.v I'mtein is ain^linteru'. i.e.. it \\ill combine with both acid 

 and alkali. Use a solution of Merck's powdered egg albumin in 

 di-tilled water, tillered. Tour a few cc. into a test-tube and a 

 similar amount of distilled water into another test-tube. Add a 

 drop of neutral red solution to both tube-. Then add very care- 

 fully dmp b\ drop froin a pipette n 51) Xa< Ml until the neutral red 

 tor i- changed yellow in each tube. I'mnpare the amounts 

 uired in tin- albumin tube with the amounts required for distilled 

 \\hal do \ ou conclude from this experiment? 

 kepeat the ahovi- but u-e i'< ali/arin a- an indicator instead 

 of neutral red and n m III 1 in-tiad of n 50 Xa<)ll. \\'hat doe- 

 thi imeiit -ho\\ ? 



i > 



