As a preventive of disease, ozone can only act by destroying organic animal poisons, in which respect it may be compared with the substances I have more than once named. With regard to the disinfecting and deodorizing powers of ozone, I would refer you to the opinions of the late Dr. Barker, contained in the Hastings prize essay for 1865. The subject of comparison, and indeed the whole subject of deodorizing and disinfecting, is there so admirably, so exhaustively discussed, as to leave, it seems to me, nothing further to be said on the subject.

Lastly, as a remedy. In the form of ozonized oil, of ozonized ether, and ozonized water, it once more ranks with a similar combination of remedies, containing chlorine, bromine, and especially iodine. Whether, in any respect, it may prove to have greater advantages than the last named trusty and ready agent, can only be conclusively arrived at by determining whether it will do what iodine will not do, and this can only be decisively made out by applying to it the test of inductive philosophy—a rigid exclusion of all that is ineffective.-Amer. Journ. Med. Sei., July, 1868., from Med. Press and Circular, Jan. 15, 1868.

RELATIVE VALUES OF FRENCH AND ENGLISH WEIGHTS AND MEASURES.

BY A. A. FESQUET.

I see in the column of Notes and Queries (American reprint, March, 1868) that one of your readers wishes some calculations showing the relative value of French and English weights and measures. Tables for this purpose are to be found in many technical works, but I think they are not so complete as those I join to this letter. You will see by the number of different values of the gramme, and of the carat weight, that "the doctors or the standards disagree."

The value I have adopted for the gramme is 15-438395 troy grains, calculated from 1 pound avoirdupois 7000 grains =

453-4148 grammes.

if

=

It may be that these data, or my calculation, are incorrect; I wish to be corrected. It would be a satisfaction to many

of your readers to know the exact value in grammes of the English standard pound avoirdupois, and how many troy grains it contains. Most authors say 7000 grains; however, I have seen 7004 grains printed somewhere.

The use of the metric system is extending more and more; but the abbreviations in writing are not always short and corresponding to the simplicity of the system, therefore I have added to the tables a series of symbols for abbreviations, which will be understood by looking at them. The system is based on the same principles followed in chemical symbols Each unit and its prefixes are indicated by their first letter, with this difference, that a capital letter is used when the prefixes are those increasing the unit.

=

We use already: kgm. kilogrammetre; we might have as well, kg. kilogramme degrees, g=gramme, instead of

or grm.

Philadelphia, March 23, 1868.

TABLES

gm.

Showing the relative values of French and English Weights and

PHYSIOLOGICAL ACTION OF THÉINE.

Chemical analysis has shown that tea contains the same crystallizable, nitrogenized principle as coffee and cocoa. Dr. Leven conceived that it would be useful to determine by experiments whether the physiological effects were the same. Having already experimented with caffeine (see Amer. Jour. Med. Sci. for April, 1868, p. 525), he determined to experiment with théine on frogs and guinea pigs. The following are his conclusions:

1st. Théine and caffeine, considered as one and the same alkaloid by chemists, seem to produce different toxic effects on animals submitted to their action.

2d. Théine is a less powerful toxic than caffeine, and it is only when given in double doses that the former produces the toxic effects of the latter.

3d. Théine also produces convulsive movements in the limbs, which Dr. L. has not observed from the action of caffeine.

4th. In other respects their physiological effects are identical. Both alkaloids seem to directly excite the heart and respiratory movements and to increase arterial tension. By exciting the circulation, they stimulate the central nervous system, the brain and spinal marrow; but they do not arrest the functions of the spinal cord and nerves. The tetanic convulsions resulting from their action is caused by the stimulation of the spinal cord. They do not abolish the functions of muscle; the heart does not cease to beat immediately after death.-Amer. Journ. Med. Sci., July, 1868, from Archives de Physiologie Normale et Patholo gique, May-June, 1868.

DETECTION OF NITROGLYCERIN.

BY A. WERBER.

To detect nitroglycerin in cases of poisoning, the author proceeds in the following manner:-The organic material to be tested is extracted with ether or chloroform, the extraction mixed on a watch glass, with two or three drops of pure aniline, and evaporated upon the water-bath. A few drops of concentrated sulphuric acid are then added, when, if nitroglycerin is present, a purple coloration appears which changes to a dark green on dilution with water. As little as 001 grain of nitroglycerin may thus be identified.-Lond. Chem. News, July 10, 1868, from (Schmidt's Jahrb. d. ges. Med., 1867, and Zeitschr. Analyt. Chem., vii, 158.)

CARBOLATE OF QUINIA.

Prof. WENZEL, remarks (Jahrbücher der Gesammten Med., Aug. 28, 1867), that carbolic acid, which in

solution acts as a

poison upon the lower animal organisms, is borne in proportionate, though large doses, by the higher animals and man, when introduced into the body in a diluted state. It was administered to some animals with advantage in their food in England at the time of the rinderpest. With bases, even weak ones such as quinia, carbolic acid loses in a great degree its irritating properties at the point where it is applied; when combined in the proportion of two equivalents of the acid to one of quinia, the compound is characterized by a slight sharpness, and a decidedly bitter taste. Professor Bernatzik proposes a preparation composed in this manner, and he hopes that it will prove an energetic disinfectant for internal use. G. Braun has given it with benefit in puerperal diseases, and Duchek in several typhous cases, and in one of pyæmia. Pills containing 1 grain of quinia with 6 of a grain of carbolic acid were given repeatedly without causing the slightest inconvenience, and according to these statements 3 to 6 grains of carbolic acid were given daily without injury. The compound was prepared by dissolving 60 parts of carbolic acid with 100 of quinia, in 300 of highly rectified spirit, filtering the solution, distilling and evaporating to the consistence of turpentine, and then mixing some extract of acorus and powdered cassia.-Amer. Jour. Med. Sci., July, 1868.