534 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



form synthetically and send to the beet root 31 grams of cane-sugar in 

 thirty days. 



General Behavior of Aldehydes. — They act as reducing agents, being readily oxidized 

 to the corresponding acid. With nascent hydrogen they are reduced to alcohols. A dis- 

 tinctive reaction of aldehydes and ketones is their union with phenyl hydrazin, C 6 II 5 — 

 NH — NIL. giving hydraxones : 



CH3CHO + C S H 5 XI1XII 2 = CH 3 .CH:N.NH.C«H S + H 2 0. 



Preparation. — By distillation of the salt of an acid with a salt of formic acid : 

 CH 3 COONa + HCOONa = Na 2 C0 3 + CH 3 CHO. 



Aceto-aldehyde. 



Methyl Mercaptan, CH 3 SH. — This is a product of bacterial action on 

 proteid, 1 and is found with H 2 S in the intestine. It is, furthermore, 

 given off on fusing proteid with potash. 2 Methyl mercaptan boils at 5°, 

 and has a strong odor. It is found in the urine, especially after eating 

 asparagus, giving to it a peculiar smell. 3 According to Rubner i the smell of 

 cooked cabbage, cauliflower, and the like, is due to methyl mercaptan. 



Methyl Telluride, (CH 8 ) 2 Te. — A gas of penetrating odor found in all excreta of an 

 animal after feeding salts of telluric, H,Te0 4 . or tellurious, H 2 Te0 3 , acid. The salt is re- 

 uuced to metallic tellurium in the body, which unites with a methyl group in some way 

 liberated in the cells. 5 Metallic tellurium may be microscopically seen deposited in various 

 cells, and the odor of (CH 3 ) 2 Te may be detected for months after the last dose has been 

 given to a dog. 8 



Methyl Selenide, (CH 3 ) 2 Se. — This is very similar to the last-named substance, but 

 more poisonous. 



Formic Acid, HCOOH. — Found in ants, and obtained by distilling them 

 with water. Present likewise in stinging-nettles and in the sting of honey- 

 bees, wasps, and hornets, although not the essential poison. 7 Its salts are 

 found in minute quantities in normal urine, and are present especially in both 

 blood and urine in such diseases as leucocythsemia, fever, diabetes. 8 Formic 

 acid may be obtained from the oxidation of methyl alcohol, of sugar, and of 

 starch, but not from the latter two in the body. Likewise by heating oxalic 

 acid, 



COOH 



cooii = HCOOH + co " 



It is found in the urine after feeding methyl alcohol and other methyl deriv- 

 atives, such as oxymethyl-sulfonic acid, or formic; aldehyde. Ethyl alcohol, on 

 the contrary, does not yield it. 9 It is the lowest member of the fatty-acid series, 

 the most volatile, and the least readily oxidized in the body. If formates be 



1 M. Nencki : Archiv fur exper. Pathologic und Pharmakologie, 1891, Bd. 28, S. 206. 



2 M. Rubner : Archiv fiir Hygiene, 1S93. :t Nencki, loe. eit * Loc cit. 

 Bofmeister: Archiv fiir exper. Pathologic wad Pharmakologie, ]s94, Bd. 33, S. 198. 



8 Beyer: Archiv fur Physiologic, Jahrgang L895, S. 225. 



7 Langer : Archiv fur exper. Pathologic und Pharmakologie, 1897, Bd. 38, S. 381. 



8 See R. Jaksch : Zeitechrift fiir ph^ulnji^lt, ('/„ ,,,;,-, ism;, r,d. 10, S. 537. 



9 Pohl: Archiv fur exper. Pathologic und Pharmakologie, 1893, Bd. 31, S. 298. 



