retained in the Pharmacopoeia; if this be heated on the water bath, 
with stirring, until it ceases to lose weight, it is converted into Adeps 
Lanas. 
In making certain ointments, the water contained in hydrous wool- 
fat is objectionable; for such preparations Adeps Lanae is preferable. 
J5THYLIS CARBAMAS. 
Ethyl Carbamate. 
( Urethane . ) 
CO< 
nh 2 
oc 2 h 5 
Ethyl Carbamate is defined as: ‘An ester of carbamic acid obtained 
by the reaction of ethyl alcohol upon urea (carbamide) or one of its 
salts.” Reaction: CO<^ 2 + HOC,H 5 = CO<™ a H + NH S 
Character. — u Colorless, columnar crystals or scales, odorless, and 
having a cooling saline taste." 
Solubility. — Soluble in less than one part of water, and in 0.6 part 
of alcohol. 
Dose.— ‘‘Average dose: 1 Gm. (15 grains).” (U. S. P.) 
Larger doses do not as a rule increase the hypnotic effect, as the 
(NH 2 ) group stimulates the central nervous system in somewhat the 
way that ammonia (NH 3 ) does. Both Ethyl Carbamate (urethane) and 
hedoncd (see below) frequently fail to produce sleep, probably owing 
to the stimulating action of the (NH 2 ) group. 
Caution. — Should be kept in well-stoppered bottles. 
This substance, generally known simply as urethane , is a member 
of a series of compounds called urethanes. They" are esters of 
carbamic acid CO 
NH 2 
OH 
which in turn is derived from carbonic acid 
CO 
OH 
OH 
by the substitution of the amido group (NH 2 ) for one 
hydroxyl group (OH). Carbamic acid is not known in the free state, 
but only T in the form of its salts. The ammonium salt is a constituent 
of the Pharmacopceial Ammonium Carbonate. 
Related Products. — Closely allied to ethyl carbamate are: hedonal 
^methylpropvlcarbinolurethane = CO< 
NH 2 
O— CH< 
euphorine 
or phenylur ethane 
5cO(NHC 6 H 5 )OC 2 H 5 ), 
neurodin , th ermodin 
(phenacetin-ur ethane) , etc. One of the latest additions to this group 
is the veronal of Emil Fischer and von Mering; this is diethylma- 
lonylurea; 
C 2 H 5 
C 3 H 5 
>c< 
CO— NH^ rn 
CO— NH >lu 
