PRICES. 389 



of fatty matter, cholesterin, and a green substance probably 

 identical with biliverdiii ; with these were traces of bile barely 

 sufficient to communicate a bitter taste to the extract, and in 

 too small a quantity to leave any carbonate of soda in the 

 residue of incineration. The aqueous extract consisted chiefly 

 of ptyalin and the extractive matters comprehended under the 

 general term of " extrait de viande," by Berzelius. The com- 

 position of the fluid part of the green evacuation may therefore 

 be thus expressed : 



Water ...... 



Biliverdin, alcoholic extract, fat, cholesterin, with traces of bile . 



Ptyalin, aqueous extract coloured by biliverdin 



Mucus, coagulated albumen, and ha3matin . 



Chloride of sodium, with traces of tribasic phosphate of soda 



Tribasic phosphate of soda .... 



Peroxide of iron ..... 



1000-00 



Professor Kersten of Freiberg has recently published a paper 

 on the cause of the green evacuations observed after a course 

 of the Marienbad waters for fifteen or twenty days. 



The occurrence of these evacuations is regarded as critical 

 and highly favorable. Kersten denies that the tint is in any 

 degree dependent on the presence of bile, and ascribes it to the 

 formation of green sulphuret of iron. 



In the paper referred to he first shows that on the addition 

 of very dilute hydrochloric acid to an evacuation of this nature 

 diluted with thrice its weight of water, there is a development 

 of sulphuretted hydrogen, indicating the presence of a metallic 

 sulphuret ; moreover, on the addition of ferrocyanide of potas- 

 sium to the filtered acid solution a bright blue precipitate is 

 observed, which becomes darker after exposure to the air, indi- 

 cating the existence of protoxide of iron. This experiment 

 shows that the green pigment is destroyed or decomposed by 

 dilute hydrochloric acid, and further, that it is a compound -of 

 sulphur and iron. He accounts for the presence of the sul- 

 phuret of iron in this way. The sulphate of soda present in 

 the water is reduced in the stomach to a sulphuret of sodium 

 by the deoxidising power of the organic matters with which it 

 is in contact, aided by a temperature favorable to such a change. 



