ADDITIONS AND NOTES TO VOL. I. 459 



oxygen, and, therefore only taking place in thin layers, as for 

 instance, on a watch-glass. 



(12) Addition to p. 137, line 20. I* have likewise found crea- 

 tine in the smooth muscles in those namely of the stomach of the 

 pig ; and Siegmundf has subsequently detected it in the muscular 

 substance of a pregnant uterus. 



Verdeil and Marcet J have found both creatine and creatinine 

 in the blood. 



(13) Note on Tyrosine, p. 142. [Tyrosine has been recently 

 analysed by Hinterberger, under Liebig^s superintendence : it 

 consists of 



Carbon 18 atoms. 59'67 



Hydrogen 11 6*08 



Nitrogen 1 7'73 



Oxygen 6 26'52 



100-00 



If tyrosine be treated with boiling nitric acid it yields, accord- 

 ing to Strecker|| a large quantity of oxalic acid ; but when treated 

 with cold nitric acid it not only yields oxalic acid, but also 

 nitrate of nitro-tyrosine C 18 H n N 3 O 16 ; which when treated with 

 oxide of silver and ammonia yields 3 Ag O -f 3HO -f C 36 H 17 N 4 O 17 . 



In addition to the sources of tyrosine mentioned in the text 

 (namely casein, albumen, and fibrin), it may be obtained from horn 

 (Hinterberger), cochineal (Warren de la Rue^[), and from feathers, 

 hair, the elytra of the cockchafer, globulin, and hsematin (Leyer 

 and Roller **) by treatment with dilute sulphuric or concentrated 

 hydrochloric acid, as well as by putrefaction. According to 

 Hinterberger, tyrosine is much more advantageously obtained 

 from cows 5 horn than from albumen, casein, &c., and it is better 

 to fuse the horn with caustic potash than to employ dilute sulphuric 

 acid. According to Piria, ft the following is the best method of 

 obtaining this body : 500 grammes of horn shavings must be 



* Walther, Diss. inaug. med. Lips. 1851, p. 8. 



f Verb. d t phys.-med. Ges. zu Wiirzburg. Bd. 3, S. 50. 



t Journ. de Chim. et de Phys. 3 Se'r. T. 20, p. 91-93. 



Ann. d. Ch. u. Pharm. Bd. 71, S. 70-79. 



|| Ibid. Vol. 72, p. 70-80. 



^[ Ibid. Vol. 57, p. 127. 



** Ibid. Vol. 83, p. 332-338. 



ft Ibid. Vol. 82, p. 251. 



