MISCELLANY. 
On the Essential Oil of Bitter Almonds. — By Mr. R. D. Grindlby. — 
There is a great discrepancy in the opinions that have been expressed 
by Chemists and Toxicologists, as to whether the pure oil of bitter 
almonds, or hydruret of benzoyle, be poisonous or not. By some the 
known poisonous properties of the crude oil of bitter almonds of com- 
merce is ascribed entirely to the hydrocyanic acid which it contains, 
while others assert that the oil freed from prussic acid is still a violent 
poison. The experiments which are mentioned by Dr. Christison and 
Dr. Pereira would appear to have settled the question, and to have left 
no further doubt, that pure oil of bitter almonds possesses no poisonous 
properties; but the assertion of the opposite opinion in the Outlines of 
Chemistry, more recently published, by Dr. Gregory, has again created 
doubts on the subject. 
As public attention has of late been so much directed to this substance, 
T felt desirous of making some experiments on it, and my results are 
as follows: — 
At first I adopted the usual plan for removing the hydrocyanic acid, 
by distilling the commercial oil with a mixture of protochloride of iron 
and lime ; the product was still contaminated with the acid, and several 
repetitions, conducted with every precaution, were attended with no 
better success; I then adopted, by the suggestion of Mr. Redwood, the 
following method which proved most satisfactory. The oil was mixed 
with an equal quantity of water, and digested in a water-bath with 
binoxide of mercury, and small quantities of lime and protochloride of 
iron; time having been alowed for the decomposition of the acid, the 
whole was introduced into a copper retort, and subjected to distilla- 
tion ; the product consisted of pure hydruret of benzoyle, while bicya- 
nide of mercury, benzoate of lime, chloride of calcium, and oxide of 
iron, remained in the retort, withbenzoine and any excess of the ingre- 
dients employed. 
The process is founded upon the strong affinity which exists between 
mercury and cyanogen, so that when binoxide of mercury and hydro- 
cyanic acid are digested together, they are both decomposed, bycanide 
of mercury and water being formed. The protochloride of iron, which 
with the lime yields protoxide, is introduced to prevent the formation 
of benzoic acid, from the oxidation of the oil; for the same reason, care 
should be taken to conduct the process with as little access of air as 
