and fitted with a cork having three perforations. Into one of these perforations insert a safety-tube, which should reach nearly to the bottom of the bottle; into the remaining perforation fit a glass tube and connect it with a bottle which is about three-fourths filled by the Distilled Water. This tube should dip about an inch below the surface of the water. By means of a second tube connect this bottle with another bottle containing a dilute solution of carbonate of sodium, to absorb any gas which may not be retained by the Distilled Water. Having ascertained that all the connections are air-tight, apply a moderate heat to the flask until the evolution of gas has nearly ceased, and during the passage of the gas, keep the bottle containing the Distilled Water at or below 10° C. (50° F.) by surrounding it with cold water or ice.

Finally, pour the Sulphurous Acid into glass-stoppered, dark amber-colored bottles, and keep them in a cool and dark place.

A colorless liquid of the characteristic odor of burning sulphur, a very acid, sulphurous taste, and a strongly acid reaction. Sp. gr. 1.022-1.023. By heat it is completely volatilized. Litmus paper brought in contact with the Acid is at first turned red, and afterward bleached. On pouring a few drops of the Acid into a test-tube containing diluted hydrochloric acid and some test-zinc, a gas is evolved which blackens paper wet with solution of acetate of lead.

If to 10 C. c. of Sulphurous Acid there be added 1 C. c. of diluted hydrochloric acid, followed by 1 C. c. of test solution of chloride of barium, not more than a very slight turbidity should be produced (limit of sulphuric acid).

If 1.28 Gm. of Sulphurous Acid be diluted with 20 volumes of water and a little gelatinized starch be added, at least 14 C. c. of the volumetric solution of iodine should be required, before a permanent blue tint is developed.

This process is practically the same as that of the former revision, and with the present improvements in detail it leaves nothing to be desired. The description and tests are, however, much extended and improved, as they needed to be; but for some unknown reason the Committee has reduced the strength of the preparation nearly onehalf. In the previous revisions, for twenty years, the strength has been about 6.4 p.c. while now it is reduced to about 3.5 p.c. This is evidently not a mistake, since the change is duly noted in the Table of changes of strength at page 455; but the writer has never seen any reason given for the change. It is quite as easy to make it of the former officinal strength as the latter, and the precautions necessary to adjust the strength and to keep it unchanged are the same in both strengths. It is an article of extensive use, for a great many different purposes, and hence it goes into a great many channels beyond those of the Pharmacopoeia, and in which the Pharmacopoeia is not known, and its uses for twenty years past are based upon, and adjusted to, the former strength of 6.4 p.c. Therefore, the present change will disturb a great many, if not all of its prominent uses, and this without any reason that the writer has seen stated. That the Committee had good reasons for the change

must, of course, be assumed, but neither the writer nor any persons whom he has asked,—some members of the Committee included,at present know why the change was made. Thus in the absence of known reasons, manufacturers who have a steady demand for the article are not likely to make the change in their product, but if they do not, or if they do, even, they should certainly give their strength upon their labels. And if they adhere to the former strength the label should not only state the strength but give a formula for reducing it from the former officinal strength to the present. The relations of the strength are such that no exact formula can be given. Each part of the 6.4 p.c. requires 0.828591+part of water to be added to reduce it to 3.5 p.c. But a more practical relation or formula is that 1 pound avoirdupois of the 6.4 p.c. strength requires 13+avoirdupois ounces of water to reduce it to 3.5 p.c., or practically 13 ounces. This makes the practical relation of 16 acid to 13 water, as the lowest expression without fractions. Therefore the physician or pharmacist who buys a one-pound bottle of the 6.4. p.c. and wants to reduce it to the present officinal strength, must transfer it to a tared bottle of sufficient size and add to it 13 avoirdupois ounces of water.

As it can be made of the former strength very nearly as easily and as cheaply as of the present, the price of the lower strength will not be proportionately less, and should not be, under any circumstances, more than 25 p.c. less, -it will be to the interest of all dispensers and consumers to buy the 6.4 p.c. and reduce it, because by this, not only in price per pound, but in bottles, freight, risk, etc., for the carrying and storing of the 13 ounces of water, there is a very considerable saving, and the requirements of the Pharmacopoeia can be as fully met as though it was bought of the officinal strength, while the other numerous and large uses of the acid, which are now so long established on the former strength, will not be disturbed.

For the destruction of all the lower orders of animal and vegetable life there are few agents so simple and effective as Sulphurous Acid, and hence it is one of the best and cheapest antiseptics and disinfectants, and one which is adapted to a great many uses. Being a gas, and one that is given off freely and rapidly from all its solutions and from burning sulphur, it is capable of being made to penetrate into all air spaces wherever germs and foul gases can go. It is, therefore, an excellent deodorizer as well as a disinfectant,

and one of easy application, but must always be used in sufficient quantity to be effective, and when in sufficient quantity,-like chlorine gas,—it renders the air irrespirable.

It must not be forgotton that in its action it is converted into sulphuric acid by oxidation, and that this acid is corrosive and destructive; and also that sulphurous acid is a powerful bleaching agent and often destroys the colors of fabrics, wall-papers, frescoes,

ete.

In the treatment of all diseases of parasitic origin it is unfailing if applied properly and of sufficient strength.

END OF VOLUME I.