CHEMICAL BASIS OF THK ANIMAL l:i\ 



of the doe/, rabbit. >r rat. Tin- colour has l.y ditier.-nt "b- | 

 been ascribed to different pigments. In -onie cases it in 

 iluc. at lea-t partl\. to tin- presence of bile-pigmentfl or their 

 derivatives, 1 tin-si- bein,u much increased in en tain d 

 as: jaundice. I'.ut in addition to these it appears that tin- colour 

 of all pi-jmcnted scrums is due to a specitic pigment. \\ln. h. while 

 it may differ (?) slightly as obtained from the l.li.nd o| dit: 

 animals, belongs in each case to the general class . 

 known as lipochromes. This view was originally put forward b\ 

 Thudichum.- who ascribed the colour to the pigment lutein, \\hi<h 

 has been already described. This view is probably e ( , rivet. inde- 

 pendently of the possibility that the colour may be in some cases 

 due partly to the simultaneous pieseii'-e of bile-pigments or their 

 derivatives. Thus it is found" that by shaking serum with -th\ 1 

 or amyl alcohol a coloured extract is obtained which cont;: 

 fatty pigment, evidently belon^in^ t<> the < lass of lipoohromet, as 

 judged liy tin- fact that it is soluble in alcohol, ether. < hloio- 

 t'orm, ben/ol, carbon bisulphide, &c., shows the two ,in t: 

 birds only one) bands in the blue part of the sjn'ctruin, and 

 the chemical reactions (p. 263) with nitric acid and sulphuri< 

 eharacteri>tic of these substances. It is in many cases identical 

 with the pigment which can be extracted from the fat of the 

 animal from whose blood the serum was obtained. Serum-lutein 

 is bleached by the action of light. 



3. Tetronerythrin 



This name wa> liist given to a substance ;loro- 



form from the red exCTOSCencefl over the . :n biid.- 4 



It was siibsiMjuently investigated by H<>pp< - Horn tin- 



same source), and described later as occurring in some -j-nnges* 

 fishes, 6 and feathci-.-. 7 More recently it ha> been f"iiiid M a pig- 

 mentary constituent of the blood of crusta. , a . s The pigment is 

 readily soluble in alcohol, ether, chloroform, ben/ol. and . ail.oii 

 bisulj.hide. i> readily bli-ached by li-ht. \iel.U the chemical reac- 

 tions with siil]ihuri'- acid, nitric acid, and iodine, \\hi--l. 



itic of the lipochioines (see p. :.''."). like theM shot) 

 alorption band near F somewhat similar to that of \anthoj.hanc 



i Flai.ni,:, > !-'' (Hilinil.in in 



senini ..f li..i>.- Imt n..t .-f ..x .. r m;r 



(IIy.lr...ilinil.in). M:i.- Mm. Soc V..1 \\\i. (1880). p. 331 (Choletdia). 



fro/6. /: '/. ///../. M'/. 



,/. ./,. Nahmeiu. 1RM Hnllit.urton. 



1 \Vur.n, ZLf.vii X'-i IM \\M 



R 

 Krnk nix rsr, 1 >'""/ l H"ihn. Al.ih. 4. l^ 1 *!. v 



Knik.-nlH.rj;, Ibid. Al.tli. :.. S ST. I M 8 **> ^ 



,./ T \. in. (IH81). j>. loan. Mn< Min.n. Proe. Roy. S- 

 \\\\ (1888), IM. I .-.-'. -iro 



- Ilallihurtun../. ../ ' Phytinl Vol. VI. (1884). p. 324. 



