482 APPENDIX. 



comes off no longer has an acid reaction or becomes turbid on 

 boiling. The mass of flesh, which has been thus washed out, is 

 then stirred with water to which l-1000th of hydrochloric acid 

 has been added. The fibre-substance of the muscles dissolves 

 very readily in this fluid. On the neutralisation of its acid, the 

 filtered fluid at first only yields a turbid jelly, so that the whole 

 fluid either vibrates like freshly solidified glue, or presents a viscid 

 semi-liquid condition ; the jelly gradually condenses, and there 

 sink to the bottom white, partially translucent flakes, which must 

 be most carefully washed. 



With regard to the tests for this substance, we may observe, 

 that notwithstanding its many points of resemblance to albumen and 

 blood-fibrin, it differs from them so essentially in some of its pro- 

 perties, that an error of diagnosis in this direction is hardly pro- 

 bable. Its behaviour towards water containing hydrochloric acid 

 (in which blood-fibrin does not dissolve, but only swells), and 

 towards nitre-water and carbonate of potash will prevent it from 

 being confounded with blood-fibrin ; while its precipitability from 

 alkaline solutions by the chlorides of potassium and sodium, or by 

 other salts of the alkalies, sufficiently distinguishes it from ordinary 

 albumen. 



The occurrence of this body, as the most essential constituent 

 of the fibrillee of the transversely shaped muscles, was first recog- 

 nized by Liebig. I have found it not only in the ordinary smooth 

 (unstriped) muscles of the stomach, the intestinal canal, and the 

 urinary bladder, but also in almost all the contractile tissues in 

 which Kolliker has detected the so-called contractile fibre-cells, as 

 for instance, in the middle arterial coat, and in the spleen. 



We are unable to form any definite opinion regarding the origin 

 of the syntonin from the albuminous matters of the food, or from 

 the albumen or fibrin of the blood, until we possess more distinct 

 knowledge respecting the chemistry of the protein-bodies. 



The uses of this substance are sufficiently obvious from the 

 parts in which it occurs ; it is the main constituent, and the most 

 essential substratum of all the contractile tissues. We are, how- 

 ever, as yet unable to decide as to the extent to which it is more 

 capable of contributing to vital contractility than the other protein- 

 bodies. 



(43) Addition to p. 385, line 14 from bottom. From a com- 

 paratively early epoch in animal chemistry attempts have been 

 made to recognise casein in the blood ; but none of them were dis- 



