CHEMICAL BASIS OF THE ANIMAL BODY. 47 



peptones or albumoses (Kiihne). The colouring matter obtained by the addition 

 of these reagents has been examined by Krukenberg 1 and more recently by Stadel- 

 mann 2 . 



CLASS VII. Lardacein, or the so-called amyloid substance*. 



The substance, to which the above name is applied, is found as a 

 pathological deposit in the spleen and liver, also in numerous other 

 organs, such as the blood-vessels, kidneys, lungs, &c. 



It is insoluble in water, dilute acids and alkalis, and neutral saline 

 solutions. 



In percentage composition it is almost identical with other proteids 4 , 

 viz. : 



0. and S. H. N. C. 



24-4 7-0 15-0 53-6 



The sulphur in this body exists in the oxidised state, for boiling 

 with caustic potash gives no sulphide of the alkali. The above results 

 of analysis would lead at once to the ranking of lardacein as a proteid, 

 and this is strongly supported by other facts. Strong hydrochloric 

 acid converts it into acid-albumin, and caustic alkalis into alkali- 

 albumin. When boiled with dilute sulphuric acid it yields leucin and 

 ty rosin 5 ; by prolonged putrefaction indol, phenol, &c. 6 . On the other 

 hand, it exhibits the following marked differences from other pro- 

 teids : It wholly resists the action of ordinary digestive fluids ; it is 

 coloured red, not yellow, by iodine, and violet or pure blue by the joint 

 action of iodine and sulphuric acid. From these last reactions it has 

 derived one of its names, 'amyloid,' though this is evidently badly 

 chosen ; for not only does it differ from the starch group in composition, 

 but by no means can it be made to yield sugar 7 : this latter is one 

 of the crucial tests for a true member of the carbohydrate group. 

 According to Heschl 8 and Cornil 9 anilin- violet (methyl-anilin) colours 

 lardaceous tissue rosy red, but sound tissue blue. 



The colours mentioned above, as being produced by iodine and sulphuric acid, 

 are much clearer and brighter when the reagents are applied to the purified lardacein. 

 When the reagents are applied to the crude substance in its normal position in the 

 tissues, the colours obtained are always dark and dirty-looking. 



1 Verhand. d. phys.-med. Gesell. Wiirzburg, Bd. xvm. (1884), Nr. 9, S. 7. 



2 Zt. f. Biol. Bd. xxvi. (1890), S. 491. 



3 Virchow, Compt. Rend. T. xxxvii. p. 492, 860. 



4 C. Schmidt, Ann. d. Chem. u. Pharm. Bd. ex. (1859), S. 250, and Friedreich 

 and Kekule, Virchow's Archiv, Bd. xvi. (1859), S. 50. 



5 Modrzejewski, Arch. f. exp. Path. u. Pharm. Bd. i. (1873), S. 426. 



6 Weyl, Zt. f. physiol. Chem. Bd. i. (1877), S. 339. 



7 C. Schmidt, loc. cit. 



8 Wien. med. Wochenschr. No. 32, S. 714. 



9 Compt. Rend. T. LXXX. (1875), p. 1288. 



