CHEMICAL HAS IS OF THK AM MAI. BODY, 



Purified lardaeein i.> readily soluble in moderately dilute 

 ammonia, and can, by evaporation, be obtained from this .solution 

 in the form of tough, gelatinous flakes ami lumps ; in this form it 

 gives feeble reactions only with iodine. If the excess of ammo- 

 nia i> expelled, the x'lution becomes neutral, and is precipitated 

 by dilute acids. 



iHii-'itinn. The gland or other tissue containing tin- body 

 is cut up into small pieces, and as much as possible of the sur- 

 rounding tissue removed. The pieces are then extracted several 

 times with water and dilute alcohol, and if not thus rendered 

 colourless are repeatedly boiled with alcohol containing hydro- 

 chloric acid. The residue after this operation is digested at 40 

 ( '., with active artificial gastric juice in excess. Everything except 

 lardaivin, and small quantities of niuciu, nucleiu, keratin, together 

 with some portion of the elastic tissue, will thus be dil\ed and 

 removed. 1 From the latter impurities it may be separated by 

 fractional decantatiou of the finely-powdered substance from 

 water, alcohol, and ether. 



In opposition to the older statements it has recently been 

 stated that lardacein may be digested by pepsin in presence of 

 hydrochloric acid. 2 The writer's own experiments lead him to 

 believe in the results obtained by the earlier authorities 



The known products of decomposition of proteids are very 



numerous, varying in nature and relative amount with the con- 

 ditions and reagents by means of which they are produced, and 

 it may be similarly, though tit a much less extent, with the kind 

 of proteid employed. These products belong for the most part to 

 well-known classes of chemical substances, and in many cases 

 representatives of several consecutive members of any -i\en 

 homologous series are obtained during the decomposition- 



A -tudy of these products has not, however, up to the present 

 time thrown any extended light upon the more minute molecular 

 structure of the proteids. and the reason is not fai It 



consists simply in the fact that we possess no guaran; 

 tenon ,,!' the purity of those proteid- which can be obtained m 

 suHicient amounts for the purposes of experiment. The\ may 

 I.e. and pmhahly are. mixture- !'. it may be, several closely .'Hied 

 rabetances, BO that the numerous products which arise duiin- the 

 d'-ci.mposition <>f what is regarded in the cxj>erinient a 



uniform Mih-tance. represent really the deoompodtfao-piodaoti 



/ proteid molecules, and thus throw no light "ii the 

 structure of any onf. Ami the matter is still furtln-i complicated 



1 Kiilincnn.l Kii.ln.-lt. '. ~.\,.f>. IM vvxoi il*65),8.66. 



a Kwtjiirin. H'/.w. nud. Jahrb. 1886, 8. 181. 



4 



