252 PRESCOTT, ON TOBACCO. 
Dr. Hassall, in his report on the adulterations of tobacco, 
says that he could not discover, in forty specimens of 
tobacco he had examined, the admixture of any foreign leaf. 
Mr. Prescott, however, states, that from time to time there 
have been discovered with the leaf of the genuine “ weed,” 
the leaves of rhubarb, dock, burdock, coltsfoot, beech, 
plantain, oak, and elm. Also peat, earth, bran, saw-dust, 
malt-worts, barley-meal, oatmeal, bean-meal, pea-meal, 
potato-starch, and chicory leaves steeped in tar-oil. Now 
this is a list that would surely arrest the most inveterate 
smoker in his course, provided he was not assured that, by 
the aid of the microscope, all these substances may be 
detected. This is the object of Mr. Prescott’s book ; not to 
enable smokers to detect adulterated tobacco, but to enable 
Government officers to prevent the sale of adulterated 
tobaccos to smokers at all. In order to do this, Mr. Prescott 
thinks that two things are necessary; first, that Government 
officers should know what leaves are; and second, that they 
should know what a microscope is. So that his book is not 
so much an account of tobacco, as it is of the things with 
which it is adulterated, and the instrument by means of 
which they are detected. It is somewhat humiliating to 
find that people who have been to school within the last 
twenty-five years should have to be taught what leaves are, 
and what a microscope is; but such is the fact, and very 
thankful such people ought to be to those who write for 
their instruction and benefit. But Mr. Prescott has not 
only written on these elementary subjects, but he has given 
in this work a series of original researches upon the structure 
of the tobacco leaf, and the leaves of several other plants, 
very useful for the Inland department, and highly interest- 
ing to all engaged in botanical pursuits. He has very 
modestly put his observations into the form of illustrations 
of the objects investigated, with descriptions of the plates. 
He first describes, minutely, the structure of the tobacco 
leaf, giving its tissues, vascular and cellular, their distribu- 
tion in the petiole, the ribs, and the blade. The epidermis 
and its appendages are especially described, and it is on 
this point that Mr. Prescott dwells as affording the greatest 
amount of evidence in judging of the purity of specimens of 
tobacco. 
Of course, all our microscopic friends who smoke know 
that the hair of the tobacco leaf is a knobbed hair. Three 
or four long cells grow up straight from the epidermis, and at 
the end of these is a compound cell, composed of five or six 
cellules. Such a hair does not seem to occur in any other 
