58 CHEMICAL PHYSIOLOGY. 



which permits entire persons to be observed for days 

 in glass chambers, and their excretions to be accurately 

 analysed and determined. By means of this method 

 it has now been found that man during sleep stores up 

 a quantity of oxygen in his body, particularly his mus- 

 cles, which is therefore ready for the production of force 

 the moment it may be wanted. This explains the 

 phenomena of activity and rest much better than they 

 could hitherto be defined. 



The faeces contain all insoluble residues of the food, 

 some decomposed and altered bile acid, changed cholo- 

 phasine, myochrome,cholesterine changed into excretine, 

 some peculiar fatty and odoriferous matters, besides a 

 little phosphate of magnesium and calcium. They vary 

 with the diet, being dark, semifluid, and of small bulk 

 after meat diet, but of large bulk, paler and more solid, 

 after bread diet. Boiled with sulphuric acid they yield 

 a matter which has a peculiar spectrum. 



The fasces of children at the breast contain choles- 

 terine, and besides caseine and undefined matter, a yel- 

 low matter soluble in alcohol, intestino-luteine. This 

 possesses one absorption-band in its spectrum, at the 

 beginning of blue. 



The anomalies of fasces are still less known than their 

 normal composition. The cholera evacuations were 

 fully described in my report on cholera. Their spec- 

 trum may be compared with stercorine on the one, and 

 acid cruentine on the other hand. 



Iron preparations taken into the stomach colour the 

 fasces black, mercurial ones green. This latter fact 

 gave rise to a fallacy now exploded, namely, that mer- 



