BY DR. LADDER BRUNTON. 425 



ir/u'rh in^lnrnrr I'nmjnlalinn. T<')UjT<tfi< ri- 

 al irhn-h Coagitl&tion OCCUrs, Although solutions of :illumiiii 

 are generally boiled in order to produce coagulation, it takes 



place much below tlu- boiling point. The tempera! lire at which 

 it. occurs some! inics serves to separate albuminous bodies which 

 could not otherwise be distinguished (s,v (JO). The method 

 of ascertaining it, is us follows: Tut some aqueous solution of 

 albumin in a test-tube; place it along with a t hermometer in a 

 beaker containing water, and apply heat very gradually till * ~ f. 

 coagulation begins to take place and tlie solution grows milky^ 

 iVom the formation of a precipitate. Then note the tempera- 

 ture of the water. If the liquid is heated over :i naked Maine, 

 it cannot be so equally and gradually wanned throughout, nor 

 the temperature at which coagulation occurs so accurately 



ascertained. 



Kl/'n-f. of A<-nh <nt<l Alkalis <> tin- YV//>r/Y/////v of (!<><i<jnla- 

 fion. The addition of very dilute acetic or phosphoric acid 

 causes Coagulation to take place at a lower temperature. The 

 addit ion of a, very lit tie sodium carbonate prevents coagulation 

 from taking place till the solution has been raised to a higher 

 temperature than is necessary in neutral solutions. A lai 

 quantity will prevent it, altogether. 



Tut some albumin solution into three test-tubes, acidulate 

 one slightly with very dilute acetic or phosphoric acid, add to 

 another a drop or two of a solution of sodium carbonate, and 

 keep the third wHliont. any addition, for the purpose of com- 

 parison. Tut a drop or two of litmus solution into each, so 

 that they may be distinguished by t heir color, or at t aeh a small 

 label to each. Plaee all three in a beaker, and warm them as 

 in the previous experiment-. As the I cm pcrat lire rises coagu- 

 lat ion will occur, first in the acid, i,e\t in the neutral, and lastly 

 in the alkaline soludoTT. '*' 



/'.'/!'<</ <>/' Hi'iilml Alknlhn' ,SV/x on Ihc 7Vwy>/-/v/////v Oj 

 Ogulation.The addition of neutral alkaline salts, such as 

 sodium chloride or sulphate, to a solut ion of albumin causes it 

 to coagulate at, a lower temperature than it would other\\: 

 do. The salts prodii"e this ell'eet in neutral, in acid, and in 

 alkaline solutions of alb;unin. 



llepeal, the previous e\ periment , dividing each solut inn into 

 two parts and adding to one of them some saturated solution 

 of sodium sulphate. In each case coa^iilat ion will take place 

 at a. lower temperature in the solution to which the salt has 

 been added than in t he corresponding one to which no addition 

 has been made. 



A - the acgtic acid alone lowers the temperature of coagula- 

 tion, and t he addit ion of nent ral salts does so still further, I he 

 solution to which both have been added will coagulate lirst. 

 Py adding a large (piantity of the salt Mid of aoetio aoid OOOgn- 



