mental change, can all the various manifestations of scrofulous disease be explained. And in going back to a humeral pathology of these diseases, and thus obeying the general tendency of modern views, Dr. Madden illustrates also the superiority of modern humoralism to the ancient, by basing his investigation on well-observed facts, and substituting close analogies for mere fancied resemblances, and thus arriving at a precise expression of the kind of change which may be presumed to take place in the blood, and to lie at the very bottom of all the outward manifestations of scrofula.

It may be said, doubtless, that we have still to ascertain what the new element is, and how generated. But it will be much to have settled the point, by a large induction of analogies, that we have as good reason to believe in the existence of some poisonous principle as the essential condition of scrofula, as to assume the same for gout or rheumatism, for ague or continued fever. That changes, too subtle even for the refined processes of modern chemistry to detect, do verily pass upon the blood, none can doubt who adopt the humoral hypothesis for diseases which most obviously of all demand it ;-and perhaps nothing more strikingly exemplifies the immense effect, upon the functions of the whole body, of changes which nothing whatever may be able to verify except their effects, than that inscrutable alteration in the blood which remains after the poison of variola or scarlatina has wrought all its visible consequences, and which is sufficient to protect that fluid, for an indefinite period, from a repetition of primary changes which blood in its normal state undergoes in presence of those morbid poisons. Nor need we altogether despair of success, as methods of investigation become more and more delicate, in further attempts at discovering, more absolutely, the nature of the presumed noxious principle. Hitherto we have arrived at no certain knowledge with respect to the materies morbi in several diseases, the phenomena and analogies which have nevertheless compelled a general acquiescence as to the existence of such an agent. We are not quite sure of what it is either in gout or rheumatism; still less definite are our conceptions of the nature of the lepra-poison, or of that of psoriasis. We allude to these, rather than to zymotic diseases and the syphilitic poison, because, though the phenomena of scrofula exhibit, in many points, a parallel to both groups of poison-diseases-to those in which the morbid element is introduced ab extra, as well as to those where it is generated within the system, it seems to us that its affinities are, on the whole, most evident with the latter. And as we have been already led by a study of the manner in which some of these are developed, and by a comparison of all the observable changes in them, to probable conclusions respecting the nature of their essential morbid elements, so may we hope to arrive at something more definite concerning the other.

In suggesting it as more probable that the poison of scrofula is generated within the system, where it may go on to be removed continually, than introduced into it from without, we are principally influenced by the general indefiniteness of the course and duration of the disease, and by the very remarkable correspondence between the diathesis of rheumatism and that of scrofula,-and by the amount of evidence we have, bearing on the production of the latter, and thereafter of the ulterior manifestations of the disease, by external conditions.

Our space will not allow us to pursue this subject any further; though there are points relating both to the general question of the existence of the poison, and to its probable source, on which we should have liked to add a few remarks. For the present, however, we must leave both of these; not without a hope that Dr. Madden may, by some future extension of the investigation on which he has so promisingly broken ground, tempt as to a further discussion of them.

The Appendix to Dr. Madden's work contains some very valuable information on the Climate of Torquay, based upon the tables published by Mr. Vivian, and upon the meteorological journal accurately kept by the same gentleman. In these are shown the mean temperature of Torquay during the different seasons of the year, its mean extreme range, and mean daily range; a comparative view of the temperature and humidity of Torquay, and in England generally; as well as a comparison of the humidity of Torquay with that of other places resorted to by pulmonary invalids;-the general result of which is to show the great equability of the Torquay climate, both as to temperature and humidity, and to correct the prevailing notion, to which the sanction of Sir James Clark's authority has given additional currency, that Torquay is, from the humidity of its atmosphere, an unfavorable place of residence for those patients, of languid constitution, who have a congested bronchial membrane, with copious expectoration.

We have reserved for comparison with Dr. Madden's tables the results of Dr. Martin's observations upon the climate of the "Undercliff." These observations have been taken regularly at 9 a. m., during the space of ten years (from December 1838, to December 1848), with the omission of only one day; and in the mode in which they have been recorded and digested, as well as in the care taken to secure to the instruments such an exposure as should cause them to give the fairest indications, we consider that they may be held up as models to such as are disposed to carry out a corresponding series in other localities. It is to be regretted that no similar information is given us by Dr. Madden respecting the conditions under which Mr. Vivian's observations have been made; and that we are therefore unable to say how far the two series afford the data for a fair comparison.

The mean annual temperature of the Undercliff, deduced from ten years of observation, is 51° 72; that of Torquay, from the four years between 1842 and 1846 inclusive, is 52°-1. These years, by referring to Dr. Martin's table, we find to present a fair average. If the cold year, 1840, or the hot year, 1846, had been included, the mean deduced from the shorter term would have been unduly low or unduly high.

The mean temperature of the seasons, at the Undercliff and at Torquay respectively, is as follows

From this it appears, that, in regard to winter temperature, there is a slight advantage on the side of Torquay, if the observations were made under parallel conditions. The range of variation, however, is a more important element in the character of climate than the actual mean; and

as to this there appears to be very little difference between the two localities.

Annual. Winter. Spring. Summer. Autumn.

Undercliff
Torquay.

For the sake of comparing these data with similar ones, obtained from other sources, we subjoin the results of corresponding observations made in London :

Annual. Winter. Spring. Summer. Autumn.

Mean temperature.

50.3

39.1
32

48.7

46

62.3
48

51.3

48

Mean extreme range 64 The mean daily range of temperature at the Undercliff and at Torquay appears to be nearly the same, so far as we may judge from a comparison of the average of ten years, given by Dr. Martin, with the results of observations during the year 1847 only, which are given by Dr. Madden. Both have a considerably less daily range during the winter months than Madeira presents; a point of no inconsiderable importance.

We may pass over the barometric observations given in equal detail by Dr. Martin, but not comprehended in Dr. Madden's Appendix, with the remark that they do not present any peculiarity on which we need stop to dwell; the average at the Undercliff being nearly the same with that of London, and the range rather less.

With respect to the hygrometric observations recorded by our two authors, it is to be regretted that they do not afford data for more exact comparison. Dr. Martin very justly points out, that no sufficient indication as to the humidity of a climate can be drawn from any observation of the dew-point taken only once a day, which is the usual method. He gives the following as the results of observations taken during seven years at 9 a. m. and 6 p. m, the hours which seem to give the nearest approach to the mean, during the winter months more especially; and with these we bring into comparison those averages of observations made at Torquay and at Clifton, which were taken, we believe, only once a day, namely, at 9 a. m.

From these observations it would seem, that the absolute dryness (as shown by the depression of the dew-point) is greater at Torquay and the Undercliff, for the year, than it is in Bristol; that in winter there is but little difference between the three places in this respect; that in spring the advantage is great on the side of the Undercliff, but that Torquay is still much drier than Bristol; whilst, in the summer and autumn, Torquay is considerably drier than the Undercliff, which is moister than Bristol in the autumn quarter. These differences manifest themselves more strongly when we bring the mean temperature into account, so as, by taking the differences between the dew-point and the temperature, to show the sensible dryness, or amount of evaporation, at each period. In the following table, this is given by Dr. Martin from two observations, as before; whilst, in the other cases, we believe that only one is relied on.

The inferences deducible from this table do not altogether correspond with those which the preceding would seem to warrant; but still they fully bear out the statement, that the atmosphere, both of the Undercliff and of Torquay, so far from being saturated with moisture, has a greater evaporating power than that of Clifton, which is usually regarded as rather a dry locality. And this seems borne out by the comparison of the amount of rain which falls at these three places respectively, as shown in the following table:

So, again, with regard to the number of days on which rain falls,—a matter of as much importance as the actual amount of rain,-we find that both these spots present a favorable contrast to Bristol; Torquay, however, having a decided superiority.

In regard to seclusion from northerly winds, both the Undercliff and Torquay possess this great advantage, that a very efficient shelter is afforded to them, without that excessive protection which becomes so injurious by obstructing the ventilation, and impeding the solar illumination of towns shut up within a narrow semicircle of hills. In both these localities, the invalid can enjoy long walks or rides, and encounter a considerable variety of scenery, without risk of severe exposure, even during the prevalence of northerly or north-easterly winds.

Dr. Martin assures us that the Undercliff is freer from sea-fogs than most places on the southern coast of England; and he believes that it has also an advantage, especially over the south coast of Devon, in regard to its electrical state,--an element in climate of which we as yet know too little, but of which we trust that much will speedily be learned. Dr. Madden has nothing to say upon either of these points.

It is obvious, then, that both these situations present great advantages to those who seek a change of climate on account of such pulmonary affections as can be removed or mitigated by a mild and tolerably dry atmosphere; and the profession is much indebted to Drs. Madden and Martin for thus presenting it with satisfactory materials for its judgment.

PART SECOND.

Bibliographical Notices.

ART. I.-Elements of Chemistry, Theoretical and Practical; including the most recent Discoveries and Applications of the Science to Medicine and Pharmacy, to Agriculture, and to Manufactures. By Sir RICHARD Kane, m.D., M.R.I.A., President of the Queen's College, Cork, &c. &c. Second Edition.-Dublin, 1849. 8vo, pp. 1070. Illustrated by 230 Woodcuts.

SIR ROBERT KANE'S deservedly high reputation as a chemist, his intimate acquaintance with the industrial occupations of the Irish, and his unceasing efforts to develope the resources of his country, have tended to bring his Elements' into great public favour; and, as appears from the preface to this edition, his work has not only enjoyed considerable patronage in Great Britain and Ireland, but, under the editorial guidance of Professor Draper, of New York, it has been adopted in the Colleges of the United States.

The general plan and character of this treatise are peculiarly suited, in our opinion, to the wants of the chemical student; for while it is constructed so as to avoid most of the questionable and unproven hypotheses of modern chemists, it omits none of their important discoveries; it dwells much more upon general principles and doctrines, than upon the wearisome details with which most treatises are crowded; and it is written, moreover, in such an easy and familiar style, as to be adapted to the capacity of every reader of ordinary intelligence.

In his attempts to avoid the errors of modern hypotheses, however, the author sometimes commits faults of a serious nature. Thus, to take an instance or two, he treats the subject of heat as if the latter were a material agent; and he speaks therefore of quantities of it, of a special heat, of atmospheres of it, and he says that the production of it, whether it be by reason of friction, compression, or chemical action, is due to the condensation of matter, and to the evolution of specific heat. (p. 95.) So, also, he speaks of electricity as a fluid incorporated with matter; and he adopts this hypothesis, not because he believes in the actual existence of such a fluid, but because the supposition is ancient, and has become a part of our common creed. (pp. 138-269.) Magnetism, again, is spoken of (p. 185) as "a form of electricity," without any recognition of the views of those eminent physicists who regard it as not identical with any form of electricity, but as correlated to it, as it is also to heat. He evidently inclines to the idea that all these agents are dynamical, not in any sense material; and we could wish that he had spoken out his views more boldly, and had made the requisite changes in the phraseology he employs.