( 11L.MICAL BASIS OF THK ANIMAL BODY. 



t<> which if nei.'e>ary ;i few drops of ammonia have been ad 

 (iv Kiv4iiriit.lv from normal urine, the in- ly if that he 



highly coloured. a solution of urobilin may In- obtained by -imple 

 agitation with chloroform, or by gently shaking it up with half its 

 volume <>f fare ether free from all traces of alcohol. Th- -th-r 

 is then removed l.y a separating I'mimd. -\ ;ip,, rated at ordinary 

 temperatures, and the residue dissolved in a small quanti 1 

 absolute alcohol. 3 



If the alcoholic or chloroformic solutions above descril-<i 

 evaporated to drvness at a low teni]>erature, the urobilin remain* 

 as a yellowish-brown amorphous pigment, which i- pra tieally 

 insolulde in water except in presence of small amounts of neutral 

 salts, very slightly soluble in either ether or ben/ol. readily soluble 

 in alcohol and in chloroform. The neutral alcoholic solutions if 

 dilute are yellow with a rosy tint, and if strong show a ;_ 

 tluore>crnee. The acid solutions are reddi>h-yello\v, or if dilute 

 bright rose-coloured and do not fluoresce. Alkaline (alcoholic) 

 solutions are yellow or yellowish green according to the concen- 

 tration and usually show a marked fluorescence, which is much 

 increa>rd on tin- addition of a solution of x.inc chloride, ap|*-ai- 

 ing now rose-coloured by transmitted light and brilliant green 

 by reflected. 



S/rf,-" of urobilin. Neutral or alkaline alcoholic solutions 

 show one absorption band between b and /'. In alkaline solution 

 the band i< frequently very faint, but is more strongly m 

 after the addition of zinc chloride, so much so that it can 

 only hi- distinctly seen after the addition of this salt In 

 solutions a similar band is seen, situated however in this case 

 iitly more toward-* the violet end of tin- spectrum. 



The methods given above for the preparation of urobilin, indi- 

 mfficiently the procedure requisite f,,r its d.-tection in sol u- 

 tioii*. A^ already stated (p. 246) the ].ositim f the abeorption 

 band of urobilin is very similarly situated to that of choletelin 

 un.l.-r d-rtain i-omliti.ins. The conflict of opinion as to the identity 

 of the two substances has been dealt with above. 



It now remains to -jive a short account of the more recent views 

 on urobilin and its relationship to other pigmentary substances to 

 which ivferenee has already been made. 8 



Mac Miinn di<tingui-hes between two forms ef urobilin 

 normal and febrile or pathological. They are both obtained from 

 mine by the same method (see above) and differ as follow* 



i M. 1m. ./..urn. d. pharm. el >l' rhim. T. xsvm 159. ThU method b 



go<xl, aa avoiding to a considerable extent any alteration of the pigmttB 



1,1-. "-< finii'ive. 



Salkowski, 7* f. phvuiol. Ch,m. Bd. iv. (1880), S 

 u- Munn. Clinical t&m. nft'rw. 189, p. 104. Gires all nectary 

 For spectra see Jl. ofPhyiiot. Vol. x. (1889), p. 116. 



