CHEMICAL BASIS OF THE A M.MAI. i;oDY. 65 



of neutral fats into ^l\,-iui t - and free fatty arid. !'> i 

 in-w attention t<> tin- exi-teii'--- of this en/yme. 1 It is most 

 it in tin- Mil. -i. in. of tin- freth gland or in its secre- 

 utl may l.e extracted fria tin- former by means of j 



i y case it is essential to ensure that the gland 

 "t iicquired an acid reaction I'.-fore extraction, and that all 

 <n in the exl .tleiit. sine.- tin- en/yme is pecu- 



liarly .sensitive to acids other than .1 i- readily desti 



\>\ thfin- Hence a dilute alkaline solution should le empl 

 ami according to Paschutin sodium Uiearbonate mixed \\ ith the 

 normal carbonate is the most efficient solvent* 



presence of tin- n/yme is tested f"i- \<\ adding tin- exti;, 

 minion .-f nil "f hitter aliiiniid>. -T ..th.-r neutral oil or fat. with 

 iiiii arahic: the mixture i> then nn.st can-fully m-utrallM-d and di- 



1 at 40, togfthtT with a minimal amount of lu-utrul .- i 

 litmu> sidutioii. In prrst-ncc uf the -n/yine tin- mass turn- 

 less rabidly red, nwin^j to the liberation of the free fatty acid. 



\ niic nature of the active agent is shown by the fact 

 that its activity is greatest at about 40, is destroyed by boiling, 

 ami is dej.eiident upon the reaction of the digestive mixture. 

 greatest in \n> : a dilute alkali, although it will >ln>\v itself 



in a neutral solution. It will also be observed that the decom- 

 position which jiialyn effects is typically hydmlytic. 



Rennin. 



tl of the mucous memhrane f tin- stomach of young 

 il>, and more especially of the calf, have been known 

 time immemorial to |M ( ^,^- a m.,>t remarkahle jH.wer of 

 HL; milk to clot, and rennet was commonlx employed l.\ tin- 

 :ie manufa't ure i. f cheese. The active agent in \<\ 

 is in more recent times supposed to be eitln-r the 

 acidity of the extract itself or tin- j.n>duction of la. 

 inilk-suirar (lactose) by means of some active j,nn< ipl.- in the 

 it/ and ffemmaraton, howev.-i. >h..u.d that this 



mtenahle ; and we now know that the sulmtance to 

 whii'h the dotting is due is MM- (o whi'h the na; 



at may be conveniently ^iven. 4 The en/ynnc nature of the 

 a^ent in rennet is tl -.\\n l-\ th-- t;. pi-al i.-l.it ..... ship 



shits in its activity to the rea !n- solution in 



it ii present,* to the t- n it \vhi<-h its activity is 



1 Comfit. Am</. T. XXTUI. (149), p. 949. Sea *bo hit Ltfmt d* 

 (IftM). p | 



:), 8.30t. 

 Arck.f. Anal. /'Ao/. J*hr ; IN*. 



4 ThU wune tttmt man conveaient than UM mora oommoolj wed exprkMU 

 ' the rranet ferment ' or ' the nilk-cardlioc ferroeat' 



5 Hmmr*n (Hweduh). S Abrt/la Malr's Brid*. lt.1 a B 111. 



/. prakt. Ck*m. (N.F.) Bd. n. (1871), & 374. See ako Al Schmidt 

 6 



