CHEMICAL BASIS <>F THK ANIMAL r."l>Y. 



inclined to regard these bodies as being really of proteid nature. 

 I Jut this is ;i point which is ;is yet l>y n<> means settled, as the 1'<>1 

 lowing consideration^ show. The Mile means at mir disposal of 

 determining tlie presence of an en/vine is that of ascertaining the 

 change which it is able to bring about in other >ul>stau<-es, and 

 since the activity of the en/vines is extraordinarily great, a minute 

 trace suffices to produce a most marked effect From this it fl- 

 |o\\stliat the j)iiritied en/vines whicli give distinct proteid iva. - 

 lions might merely consist of very small quantities .,f a true 

 non-proteid en/vine adherent to or mixed with a residue of in. -it 

 proteid material Again on the other hand it is similarly possible 

 that the purified en/vines which have been described as devoid of 

 juot -id reaction really consist of some inert non-proteid material 

 with which a trace of what is ivally a true jnoteid en/yme ; 

 mixed, the amount of enzyme being too small to yield any of tin- 

 reactions characteristic of proteids. The occurrence or absence of 

 proteid reactions in a solution of an en/yme cannot therefore set- 

 tle the nature of the enzyme, and for similar reasons a mere anal- 

 ysis of the separated enzyme is also inconclusive ; the balance of 

 appears to be in favour of the view that the 



are_proteid in nature. Imt this is still an OJM-II question. 



Many nf the puritied enzymes have been analy/ed and tli- r->ults 

 slinw in many cases a percentage of carbmi c..ii>ideralily ! \\<T than 

 that (f a true proteid. Kulim-'s pure>t trypsin li:id tin- f>llo\\ ing 

 pn-, ,-ntage coinp.sitinn : C = 47'22 48-09 ; H 7'1"> 7. 1 1 : 

 N = 11' ;'.) 1::-tl : S = 1-7:5 1-Sf, F..I- ntli.-r anal 



Aug. Schmidt. 1 1 1 iii'ncr.- I'>artli. a I!ut >c.- al>.> \N'urt/. * and Lo\\ . 



The en/ymes are possessed of certain properties, nmiv o 

 common to them all. by means of which they may be sep ;i 

 from the tissues in \\hich they primarily occur, and i-olated fioin 

 tlic -olution- \\\\\< obtained Soluble in wat.-l. they may b. 

 ijiitated unchanged from this solution by the addition - 



absolute .-ill-oil. !. They may also in man\ 

 precipitated from their a(|iieons or other solution by satu: 

 with neutral ammonium ^ilphate 1 - They arc convenient 1\ -olu 



ble in glycerine 1 from which thc\ may a- bcfoie ] pie.'i] 

 bv an exceSfl of ale,. hoi. None of the en/\ ditl'usihle and 



,a\ readily be ! :iv admixed ditlu-ible 



1 /tiini'i Iii.-ii. Tiil)iiii;.-ii, 1-71 



\ i Bd ^ i-:.' - 



/ .lal.rs. M 



' < /, /. r K( (1880), ] 1879 I XOLp 



I 1!,| \\vii (1R82). S 



Ktthn< I \and.d.maturk.-med \- Ili-id.-ll,. m IHH6, S. 46.1 AI- ''.ntralb. 

 ,.,/ , . ;i ik<>w(KiiH.-iun). **> Bt 



i.-h. niii K . i '. 



