THEIR CHEMICAL RELATIONS. 71 



tuents, amongst which there were 7*24 parts of casein. He also 

 found in the middle coat of the carotid, which, as is well known, 

 contains a smaller quantity of elastic fibre, but far more contractile 

 fibre-cells than the aorta, 39$ of soluble constituents, of which 21 

 parts were casein. Moreover Schultze found that this interstitial 

 fluid had a faintly alkaline reaction, and contained in addition to 

 the casein and salts, small quantities of two substances, one of which 

 was coagulable, and the other non-coagulable by heat. 



My own observations on the juice permeating the contractile 

 tissues have shown that the fluid obtained from the muscular coat 

 of the stomach of the pig has a distinctly acid reaction, although 

 not in so intense a degree as that derived from the striped muscle; 

 the analogous fluid of the middle coat of the arteries (the ascending 

 and descending aorta, and the carotid of the ox) reddened litmus 

 paper slightly, but quite decidedly. The fluid from the tunica 

 dartos exerted no reaction on vegetable colours. Schultze found 

 that the juice of the middle coat of the arteries was alkaline, which 

 may be owing either to the admixture of the alkaline fluid of the 

 cellular tissue, or to the occurrence of incipient decomposition. 

 The middle coat of the arteries and the tunica dartos yield more 

 casein and less albumen than the muscular coat of the stomach of 

 the pig; the latter is as rich in albumen as is the juice of the 

 animal muscles. 



Creatine occurs in much smaller quantity here than in the juice 

 of the striped muscles ; but as the inadequate amount of this sub- 

 stance precluded the possibility of making any elementary analysis, 

 the crystallometric determination constituted the only evidence of 

 its presence. Besides a small quantity of lactic acid, we find 

 acetic and butyric acids. The ratio of the potash to the soda was 

 as 38 : 62 in the juice of the smooth muscles of the stomach, and 

 as 42 : 58 in that of the middle coat of the arteries. The soluble 

 phosphates were to the insoluble as 82 : 18 in the muscular fluid 

 of the stomach, and as 79 : 21 in the fluid of the middle coat of 

 the arteries. 



Siegmund* has recently found creatine, acetic acid, and 

 formic acid in the juice of a pregnant uterus ; and Walther t has, 

 under my superintendence, extended the above-mentioned micro- 

 chemical investigations regarding the fibre-cells, and the chemical 

 analysis of the juice by which they are moistened. 



All these relations, which are at the present time undergoing a 



* Verh. der phys.-med. Ges. zu Wurzburg. Bd. 3, S.^50. 

 t Diss. iiuuig. med. Lips. 1851. 



