CHEMISTRY. 191 



Ccal. When the carbon in this series combines with 3 atoms of 

 h3^drogen, it produces the radical methyl CH3, from which various 

 compounds may be made, as follows : — 



Hydride of methyl (marsh gas), CH3H. 



Chloride of " CH3CI. 



Iodide of '♦ CH3I. 



Bromide of '* CHsBr. 



Fluoride of " CHsFI. 



Cyanide of ♦' CHsCN. 



Nitrite of '» CH3NO2. 



Methyl alcohol, ™3 i O. 



In these the radical remains always the same, and these com- 

 pounds are, in fact, salts of the radical. 



To come to the particular subject of this article, — if we take 

 the hydride of methyl, or marsh gas, in which the carbon molecule 

 is said to be saturated with hydrogen, and subject it to the action 

 of chlorine, the chlorine can be made to replace the hydrogen, as 

 follows : If 1 part of the hydrogen be replaced by chlorine, we 

 have chloride of methyl, CH3CI ; if 2 parts of the hydrogen be 

 replaced by chlorine, we have a new radical, methylene CIP, 

 combined with 2 of chlorine, forming the bichloride of methylene, 

 the subject of this article. If 3 parts of hydrogen be replaced by 

 clilorine we have the radical formyle CH with 3 of chlorine, form- 

 ing the terchloride of formyle, or chloroform, CHCls* If the w^hole 

 of the hydrogen be ref)laced by chlorine, expunging altogether 

 the radicals of carbon with hydrogen, the resultant compound is 

 the tetrachloride of carbon CCI4. 



All these compounds possess the power of producing anaesthesia 

 when inhaled as vapors by men and animals. This was well known 

 of the last two. This knowledge in regard to the first two we owe 

 to Dr. B. W. Kicliardsou. — Medical Times and Gazette, Nov.^ 1867. 



ON FERMENTATION. 



At a meeting of the Bavarian Academy, in May, 1868, Liebig 

 delivered a lecture on fermentation, in which, after alluding to 

 certain alleged errors of Pasteur on this subject, and to the well- 

 known fact that fresh pare beer-yeast left to itself, in the presence 

 of water, disengages carbonic acid and produces alcohol, he states 

 that he had found that the power of yeast to excite fermentation 

 is retained as long as this process is going on ; at its close putre- 

 faction sots in. He regards this process as a vital act in the inte- 

 rior of the cell, and as the immediate cause of the action of 

 yeast in the fermentation. When a solution of sugar comes into 

 contact with the yeast cell, the inner decomposition of the latter 

 is retarded, and the molecules of sugar in contact with the cell are 

 decomposed. One hundred parts, by weight, of yeast left to 

 themselves, furnished 9.18 per cent, of alcohol. Pasteur has 

 assumed that this alcohol is produced from the cellulose of the 



