CHKMK \i. BASIS "i nil: ANIMAL J;OI>Y. : 



iSim^i-. 1 A- tin- rr.-ult nl' tlh->e. \arion-. formulae havi- IMVII proposed 

 liy the several oli-.erver-. Very little real importance can ho \\ever he 

 attached t these formulae. \r. M l>iveli>el oh-er\e>. in >,> large a 

 molecule an analytical emu- of -01 p.c. \\ould h:i\e tin- same ini|ir- 

 tance a- would one of -1 j,. ( -. in ordinary aiialv.--. Tli--\ ;_M\e u- a' 

 .in idt-a of the ntinlinul lua^nit mli- of lh- pmti-iil nioli-culf. I'lii 

 apart from this tln-y tlimu n ...... uv lij^ht on tin- >nlijt-.-t than alr.-al\ 



(1 in Lii-lirrktihn'- oldi-r formula. 



General reactions of the proteid*.* 



\. Heated with strong nitric acid, they or thrir s.ilutiui> turn 

 \fllo\v. and this colour is, on the addition of ammonia. <>r caustic 

 soda or potash, changed to a deep orange hue. (Xantlmjuntci. 

 reaction. ) 



If much protoid. except albumoses and peptones, )> present a 

 yellow precipitate is obtained at tin- same time. \Vitli less pn,- 

 teid their solutions merely turn yellow on Imiling and nrange on 

 the addition of the alkali: if only a trun- of proteid is present n<" 

 yellow colour is observed until after the addition of the alkali. 



_' With Millon's reagent 3 they give, when present in >uth- 

 cient quantity, a precipitate, which turns red on heating It they 

 are only present in traces, no precipitate is obtained. l>ut men-lv 

 a red colouration of the solution when heated., 



If mixed with an excess of concentrated solution of sodium 

 ite, and one or two drops of a dilute solution of cupi; 

 pliate. a violet colour is obtained, which deepens in tint on ln.il- 

 iii'_ r ( 1'iotrowski's reaction. 4 ) 



The above serve to detect the smallest traces of all pi 



4. Render the tluid >tn>ngly acid with acetic acid, and add a 

 feu drops of a solution of ferrocyanide of potassium: a \-\ 



-hews the presence of proteids, except true peptone- and 

 >ome forms of allum; 



1,'ender the tluid. a- l.efore. strongly acid wit i: 



add .in equal volume of a coin-, nt rated -olution of sodium >ul- 

 phate. ami boil. A precipitate i- formed if pi I l"-p- 



present 



M, <l. ,'l"/^. " fall' Mrm. 1KH7. Sn. 5J- 

 :lul,ii. fn.ni .!.:'.- !! 

 \i\ S.M9 Cliiti.-ii.l.-n an.l Wliit.-li..uw. ^ !>hyx>1. <'!> ) V n 



* Consult in all ca. 1 1..,,,.,. RerlerVi //.//"/, ,/. ;/,y"/. path. r/,/- m . Annl^c 



also Kniki-nl.Tu'. >>'-' U / \ -- \r 



I xxriii. (1849), |. ' 



/ II I / IM. vx,. 



