518 
HOW TO PRESCRIBE AND WEIGH IN GRAINS. 
At the conclusion, several gentlemen expressed their approval of the paper, and the de¬ 
sirability of such a practical application of dialysis as that described by Mr. Whitelaw. 
North British Daily Mail, Feb. 27, 18G4. 
HOW TO PRESCRIBE AND HOW TO WEIGH IN GRAINS. 
Although the toils of practice have compelled us, as they have most of our readers, to 
look upon chemical manipulation as a thing only to be taken up on some rare occasions, 
yet, sitting with a good balance and set of accurate grain-weights in our study, we 
cannot help wondering why so many who prescribe and dispense, and why the Medical 
Council which issues regulations for both processes, should prefer an intricate and ob¬ 
scure system of weights to one that is simple and obvious at first sight to every one. 
In our present remarks we confine ourselves to dispensing and prescribing as for 
manufacturing, that is no business of the practitioner. The Medical Council have 
thought fit to give formulas for the manufacture of drugs on the large scale, which 
manufacturers may laugh at or adopt, as they please ; and for processes such as these, 
the pound, with its even binary divisions of half, quarter, eighth, etc., and the ounce, 
with similar divisions, may be convenient and sufficient. 
But we do not prescribe pounds or ounces for our patients. The real unit for this 
purpose is the grain. Every one who prescribes knows how many grains or fractions of 
grains he wishes the patient to take; and whether he direct one dose or many to be 
made up, the necessary calculation is trivial, and involves no difficulty whatever. And 
it is far easier to write down any given number of grains at once, than it is to first re¬ 
duce them to drachms, or fractions of drachms, or scruples. 
It will be more convenient under this new system to use Arabic numerals than Roman. 
Most of us now write in English the directions how medicines are to be taken. We 
have done so, since a chemist’s lad once translated “ cyath. vin. aquae,” as “ a glass of 
wine and water.” The substitution of the Arabic numeral will be but one step towards 
abolishing Latin altogether, a. thing which, however regretted, is inevitable. 
Prescriptions are already half English. When we see “ grs. xx.,” we are fain to ad¬ 
vise the prescriber not to jumble Latin and English together in one phrase, but to choose 
whichever’ of the two tongues he understands best, and write wholly in that. 
Suppose, then, we wish to write a prescription for eight doses, each containing eight 
grains of carbonate of ammonia, ten of bicarbonate of potass, and fifteen of nitrate of 
potass,— 
|SL Ammonite carb., gr. G4; potassa? bicarb., gr. 80 ; potasses nitratis, gr. 120 ; aq. 
destillatse, fl. oz. 8 ; m. ft. mist. 
Sig.—“ One fluid ounce by measure to be taken every four hours, with ^half a fluid 
ounce of lemon-juice, and the same of water.” 
Such a mode of prescribing quantities would answer every purpose. There could bo 
nothing gained by writing “ gr. lxiv.,” nor yet “ 5 j. et gr. iv.,” instead of “ gr. G4,” and 
so with the other quantities. To use scruples or drachms and Roman numerals would 
be to get into a calculation for no other purpose than to get out of it again. 
Suppose a man has to perform a simple chemical determination,—say, the solid con¬ 
tents of a decigallon of water from some water-works,—first he weighs a capsule, which 
equals, say, 413‘98 grains ; ( 2 ) after evaporating the water therein, and drying at 250% 
it weighs 41 G‘4 grains; (3) after drying still further, 41G'35 grains. This number is 
adopted, giving as the total solid impurity, viz. the difference between the first and third 
weighing, multiplied by ten, as per gallon, 23‘7 grains. 
These results are seen at a glance. But what chemist, except his head were stuffed 
with straw, would write down, instead of the above figures, “ Weight of capsule, 5 vj., 
3ij., gr. xiij., et xcviij. partes grani e centum; after evaporation, Jvj., 9 ij., gr. xvj., et 
xxxv. partes grani e centum; weight of solid residue per gallon, 3j., gr. iij., et septem 
partes grani e decern ”? 
If chemists do not vex their souls with these antique intricacies, why should we ? But 
if the manner of expressing quantities in grains be easy, infinitely more so is the actual 
weighing, if, instead of the odious Apothecaries’ weights, we have a set of plain grain- 
weights. 
With the Apothecaries’ weights they give 5 ij., 5 j., 3 ij., 55 s., 3j., 3ss. ? besides grain- 
weights stamped to represent G, 5, 4, 3, 2, and 1 grain. 
