Extracted from the Transactions of the Medical Society of the 
State of Pennsylvania, for 1877. 
THE METRIC SYSTEM, 
Bv HUGH HAMILTON, M.D., 
HARRISBURG, PENN. \ 
No one who has travelled abroad but esteems the decimal system 
of our coinage a nearly perfect means of representing aggregates of 
all kinds of cost. 
The clumsy pounds, shillings, and pence of England are only used 
because London is the commercial centre of the world. 
The conceptions of the French Revolutionists of 1798, by their 
conduct overturning many honored customs, nevertheless brought 
into being the metric system, or more properly the decimal scheme, 
which developed itself here as the current coin of the United States 
through the influence of our own inventive Jefferson;-the destiny 
of which coinage is to- be universal. To complete the effort begun 
then to simplify commercial terms, Acts have been passed by Con- 
gress legalizing its use; though not yet adopted by the departments 
of Government. 
Each State is furnished with standards in this new method. A 
careful survey of this grand idea-The Metric System-exhibits 
its breadth, and shows it to be scientific in the highest degree. I 
have been enabled, by the courtesy of the Deputy Secretary of In- 
ternal Affairs of this State, to show the United States metre divided 
into deci-metres; a deca-kilogramme, kilogramme, and demi-kilo- 
gramme, with the gramme and minute subdivisions; also a litre and 
deca-litre. 
By the kindness of the Deputy Secretary of the Commonwealth 
of Pennsylvania, I am permitted to exhibit the standard U. S. yard, 
gallon, quart, pint, half pint, and gill, and from sixty pounds to 
fractions of an ounce. 
The unit of measure is called metre from the Greek, metron 
meaning measure; it is one ten-millionth of a quarter of a meridian 
of the globe. The term " French-yard" is confusing, and should not 
be used ; it expresses nothing, indeed far worse than the real name 
metre would convey. 
The metre is divided for convenience into tenths, hundredths, and 2 
THE METRIC SYSTEM. 
thousandths, these divisions being respectively called deci-, centi-, 
and milli-, from Latin roots corresponding to such terms. 
Multiples of the unit are called deca-, heclo-, and kilo-, severally 
ten, hundred, or a thousand times, from Greek sources. 
The units are- 
First, the Metre for measure of Length. 
Second, " Litre " " Volume. 
Third, " Stere " " Solidity. 
Fourth, " Are " " Surface. 
Fifth, " Gramme " " Weight. 
The application of these names preceded by their di visibles or 
multiples, creates at once a uniform way of ascertaining necessary 
length, capacity, etc. 
The facility of computing the relation which vessels sustain to 
given quantities is rendered apparent merely by noting that a litre 
is one cubic deci-metre, and a gramme one, cubic 
The correlation of weights and measures is shown to a still greater 
extent by observing that- 
A Stere is one cubic metre, an Are is one hundred square metres. 
The unit of weight, a gramme, does away with the three variable 
pounds, Avoirdupois, Troy, and Apothecaries', which awkward 
English customs have fastened upon us. To secure a universal 
unit we reduce the English measure to inches, cubic-inches, square- 
inches, and grains, only to be done by laborious multiplication and 
again by compound division. 
For instance a standard gallon, U. S.- 
Contains . . . 231 cubic inches. 
Weighs . . . 8 3 pounds Avoirdupois. 
Or do. . . . 5837'2TVoS(j% grains Troy. 
Temperature . . 39.83° Fah. 
Barometer . . 30.00 inches. 
Standard bushel- 
Contains . . . cubic inches. 
Weighs . . . n tV/jt 
Temperature and pressure above. 
Avoirdupois pound- 
Contains . . . cubic inches. 
Liable to error from mere exertion, showing plainly the need of some 
comprehensive exponent of quantity. 
The whole metric system depends upon the Metre, hence the 
name; and the Gramme is one cubic centimetre of water at 39.21° THE METRIC SYSTEM. 
3 
Fahr., 30 in. Bar., or 4° C., and 834 mm. Bar. A litre is one deci- 
metre of water, containing one thousand cubic centimetres, and weigh- 
ing one thousand grammes. Hence it supplies this requisite integer 
by fixing one for the three English measures of length, land, sur- 
veyor's, and nautical. 
For the three English measures of volume, wine, apothecaries', 
and dry, one. 
For surface and solidity one to one, while Avoirdupois, Apothe- 
caries', and Troy are absorbed into one; thus giving five units for 
eleven, which are even unreducible to a common one requiring the 
four above mentioned, namely, inches, cubic inches, and square, 
as well as grains; while the metric mode resolves itself into two 
mutually related to each other. Wherever the use of the metric 
system has been properly explained and understood by scientific 
bodies, its adoption was not long delayed; the evident ease of 
representing and calculating mathematical and chemical formula 
being so apparent and desirable. Its freedom from error and the 
vulgar fraction, besides the readiness by its use that manual mistake 
could be detected, recommend its introduction. 
The continent has almost universally appropriated this method; 
even Great Britain has succumbed to the general advance, its learned 
societies endeavoring to remove the " Three barleycorns make an 
inch" from its statutes, and the barbaric emblems from medicine, by 
substituting the more modern decimal for the Egyptian symbolism 
of 5j and §j. Incidentally I might mention that the ancient Egyp- 
tians about 3400 years ago! used these signs:- 
Unit or Tenat 
± « u z 
2 
Di-DrachmO 
By placing the Di-Drachm above the | Tenat we get a sign like 
this ° ; dispensing with the lower segment we may easily imagine it 
written for brevity 
The Honorable Mr. Layard, in his discoveries about Nineveh, 
found in the library of the famous Sardanapalus, King of Assyria, 
B. 0.771, units of surface, weight, and volume employed, derived from 
a single linear measure based upon the sexagesimal system, that is, 
divided or multiplied by sixty, which combined, it is said, the advan- 
tages of the decimal and duodecimal notation.2 
1 From American Chemist, vol. vi. p. 167, article by H. Carrington Bolton, 
Ph.D. 
2 Boston Med. and Surg. Journal, notes, vol. xcvi., No. 22. 4 
THE METRIC SYSTEM. 
The Jewish nation after their captivity brought with them the 
germs of a decimal system as shown by the following table:- 
A Cotyla ... 10 ounces avoirdupois exactly. 
An Omer . . . 100 " " " 
An Epha . . . 1000 " " " 
A Chomer1 . . 10,000 " " " 
Certainly we should endow whatever professes to be scientific 
medicine, with such essentials as a short, clear, and decisive manner 
of representing quantities. After once using the metric system in 
prescribing by grammes, divisions, or multiples thereof, one could 
scarcely be induced to return to the uncertain signs of the apothe- 
caries. 
The Dispensatory and Pharmacopoeia give the specific gravity of 
many substances; the relation sustained between weight and bulk 
would soon determine them for use or detect adulteration, for 
example, 
1000 cubic centimetres of water measure one litre and weigh 1000 
grammes. 
1000 cubic centimetres of milk measure one litre and weigh 1032 
grammes, hence specific gravity of milk 1.032. 
Objection might be urged that the different specific gravities would 
militate against the use of this method. Three general vehicles form 
most prescriptions-the diluted tinctures, water, and the syrups. 
The two former are of nearly equal gravity, while the latter is but 
one-third heavier. The essential portions of medicines form but 
small proportions of their bulks, and do not materially increase the 
volume of prescriptions.2 
The uses of the metric system to State Medicine is obvious. 
Thermometry, now occupying so prominent a position in the diag- 
nosis of disease, has a decimal gradation in the Centigrade Ther- 
mometer, that commends itself to our use for similar reasons that 
the weights and measures do. The melting of ice in water being 
placed at zero, while the point at which the mercurial column rests 
when water boils is indicated as the second initial. The space 
between these indices is divided into one hundred parts constitut- 
ing a degree. These degrees may be subdivided similar to any scale. 
Summing up the whole subject the Metric System impresses one 
with its decimal order, its purely scientific character, and entire 
1 D'Oyly and Mant, Commentaries on the Bible, Art. Weights and Measures by 
Bishop of Peterborough. London, 1856. 
2 Am. Journ. of Pharmacy, February, 1877, Prof. Maisch. THE METRIC SYSTEM. 
5 
adaptability. Why should medicine linger to adopt what chemists, 
engineers, physicists, and other professional men who have to do 
with facts and figures so heartily indorse and approve ? One can 
hardly peruse a continental work without finding either the use of 
the gramme for weight or the centigrade degree for fevers. 
Germany, although it despises France and her institutions, gives 
parts in her Pharmacopoeia. 
Boston has advanced to the use of the metric notation. The New 
York Medical Society, awakened to the issue, resolves to abandon 
the heathenish figure which clings with such pertinacity to all pre- 
scriptions, and this Medical Society of the State of Pennsylvania 
should recommend similar action to the scientific and enlightened 
physicians composing her body.