CHEKIOAL BASIS <>i' Tin: ANIMAL BODY. 



teristically into a jelly even when it contains as little as ] j.. c. of 



also readily soluble in tin- cold in dilute acids and 



alkalis. The proteid reactions of gelatin are so feeble that they 



must IM- regarded .is din- entirely to unavoidably admix. -d traces of 



;d impurities; more particularly i- it to !..- noticed that the 



usual ivai tion of pmteids with Millmi's reagent i> entirely want- 



: which indicates tin- probable absence of aromatic (hen- 



111 its molecule and orn->j..inds t" tin- ah>.-!: 

 ti amon^ the products of its decomposition. Notwithstand- 

 ing that it i- in no sense a prteid, its percentage composition ap- 

 mates to that of tin- latter lass of substances and maybe 

 D as C = 50"76, H=7'la, () = L'.",i'l, N = 1S-.TJ, from which 

 it apju-ars t-i contain distinctly less carlion than do the pi..- 



i Uo Stated to contain no sulphur when pure, hut ordinarily it 

 :ns a .-mall amount ( ." p. <-.).' C. -latin i- pie. i]pitat--i hy luit 

 few salts, vi/.. : mcicuri- chloride and the douhle i<Klide of mer- 

 cury and potassium in acid solution. Several acids on the othei 

 hand ]>iecipitate it readily, such as jhos].hotungstic and meta- 

 phoephorie, also taurocholic and tannic. Of the two last-named 

 \i. -Ms an njialescciice in presence of 1 part of 

 11 in 300,000 of .solution, and the latter in still morv dilute 

 - The ).re< -ipitaliility with tannic acid seems to depend 

 on the j^resence of neutral salts. 8 The specific rotator}' power of 

 :i in aijueous solution or in presence of a trace of alkali i> 

 to be i ")=- 130 at 30 C. and to be reduced to -111' 

 or -114 on the addition of more alkali or acetic acid. 4 This 



Mnlirminx- 



When decomposed in seal tul>es \\ith caustic-1. . latin 



\a on the whole the same products as do the proteid-. ' with 



\.-ejition of ty rosin ; neither tin- m.r any ..tlu-r substance of 



illy ai-i'inatic >.ri.- is ,\,r .htained during any decom- 



posit: latin, whether ly chemical or jmtn-faetive |n.K-fS8ea.* 



volon^ed lioilin.u with hydrochloric a. id it lycin 



ucin. ^lutamii- a. id. and ammonia. 7 and with sul- 



id aspartic acid as well. 8 



I prolonged boiling with water (1 } i.e. so- 

 lution hoiled for 30 hours), or sh -.it -nt in a I'.q.in's diges- 



1 IIammnrtn 'A. f. pkyilol. Chm. Bd. in. (18S5), 8. 905. 



Mavitthyl - 95 



\N>ik.-. CM 

 1 .1 I. I'.ir /'.-- TuLingeo, 1864. Abo in Hoppc Scylcr' mtd.<ktm. Unttrt. 



SchfitaenberKer ct Bourgeois, Comfit. Km,! I i \ \ \ 1 1 , i ?). p. MS. 



See Abut, in Mljr' Brrirkt. 1876. > u JeunerK, J* / 

 Cktm VI. Wojl Xt.f. ftytiol. Cktm M 



m 



UW Bd i xxx (1879), i- A'.ih .limi lift 



<*. 



,4ii<inl. Ct.,m M. u. (1878). S. 299. Hire* liionUore down 

 to that date. TaUriooff, Compt. Remd. T. xcrtt. (1889), p : 



6 



