From the time of the sects of the Peripatecians and Epicureans, the controversy of the divisibility of matter has been agitated, and is not hitherto determined.

The discoveries of Boyle and Leeuwenhoek have been urged by the advocates for the divisibility of matter, as a confirmation of their opinion on this subject. Mr. Boyle demonstrated the practicability of dividing a grain of gold into 1800,0000 visible parts. He likewise dissolved a grain of copper in spirit of sal ammoniac, and, mixing it so dissolved with a certain quantity of water weighing 28,534 grains, a blue tincture was given to the water in every part. He inferred, then, that there must be in every visible part of the water a small particle of copper. Now the water measured 105,57 cubic inches, and in a cubic inch there are 21,600,0000 visible parts; consequently, a grain of copper was divided into 2,278,800,0000 small visible parts.-Leeuwenhoek discovered in some water three kinds of animalcules, of which the diameters were to one another as the numbers, 1, 10, and 50; the diameter of a common grain of sand was to that of the smallest of these animalcules as 10001; and consequently its magnitude as 100,000,0000: 1. Moreover, these animalcules were seen to swim in the water, had muscles, nerves, blood-vessels, &c. Of what an inconceiveable smallness, then, must a globule of their blood be! We may describe its magnitude compared to that of some other object by means of numbers, but we cannot form any idea of it. Mr. Addison expresses himself on this subject, in the Spectator, with great elegance and perspicuity; as quoted by the present translator :

"Let a man try to conceive the different bulk of an animal, which is twenty, from another which is a hundred times less than a mite, or to compare in his thoughts, a length of a thousand diameters of the earth, with that of a million, and he will quickly find that he has no different measures in his mind, adjusted to such extraordinary degrees of grandeur or minuteness. The understanding, indeed, opens an infinite space on every side of us; but the imagination, after a few faint efforts, is immediately at a stand, and finds herself swallowed up in the immensity of the void that surrounds it: our reason can pursue a particle of matter through an infinite variety of divisions; but the fancy soon loses sight of it, and feels in itself a kind of chasm, that wants to be filled with matter of more sensible bulk. We can neither widen, nor contract the faculty to the dimensions of either extreme. The object is too big for our capacity, when we would comprehend the circumference of a world; and dwindles into nothing, when we endeavour after the idea of an atom.??? SPECTATOR, No. 420.

*See Lucretius, first book.

sand.

The translator says that the sand was of that sort called scowering

REV. AUG. 1799.

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These

These discoveries of Boyle and Leeuwenhoek (as we have already stated) were brought forwards in support of the opinion of those who maintained the infinite divisibility of matter, as it is called. The mathematical proof of the divisibility of matter was likewise forced into the same service.-The advocates of the opposite opinion, however, contended that neither the physical experiments nor the mathematical demonstration were conclusive against them; that there was no clear and decisive experiment to shew that a body was composed of divisible parts; and on the contrary, that nature, in the analysis of matter, appeared to stop at a certain degree, and to be fixed and determinate. In regard to the mathematical proof, this argument did not apply; the divisibility of a geometrical body not being analogous to the divisibility of a natural and physical body, because the idea of extension involves only that of parts united and co-existing, of which the number is arbitrary; not that of parts actual and determinate, of which the number in any physical body must constitute its essence, and be determinate. The subjects treated in this first number are

Of the Oak.-The nature of it's Production; the different Degrees of Goodness in Oak Timber; and the Causes of that Difference. The Author's Opinion as to the proper Season for felling Timber.'Of the Fir-The different Degrees of Goodness in Fir Timber, how discoverable; the minute Vessels which enter into the Composition of this Tree described at large.'

Of the Weevil or Corn-beetle.-Wherein the common Opinion that this Insect is bred in Corn spontaneously, is shewn to be erroneous; the true Nature of its Generation explained; with the Means to preserve Corn from its Infection.'.

Of the Maggot or Caterpillar infesting Corn in Granaries; the Nature of its Generation explained, and the Means to prevent its Increase pointed out

Of the Spider. The following observations were made on those kinds of Spiders which are found in gardens, where they fix their webs to vines, herbs, and shrubs.'

Of the Silk Worm.'

On the nature of the scales of Fishes, and how the age of those Animals may be determined by observation of the scales; The Author's reasonings and opinion respecting the Longevity of this part of the Animal Creation.'

The Author's refutation of the doctrine of equivocal or spontaneous generation in the instance of the Sea-Muscle, with a particular description of that species of Fish.'

Of the Muscle which is found in fresh water; a particular description of its internal formation, and of the manner in which its young are produced.'

We have not heard that any additional numbers of this work have appeared when they reach us, we shall report them to the public.

Wood....e ART.

ART. XI. Further Observations on the Variola Vaccine, or Cow-pox.
By Edward Jenner, M. D., F. R. S. F. L. S. &c. 4to.
Law, &c. 1799.

2s. 6d.
THE
HE farther observations here announced on this interesting
subject relate to

1st, Facts which point out the fallacious sources whence a disease imitative of (resembling) the true Variola Vaccine might arise; with the view of preventing those who may inoculate, from producing a spurious disease.' 2dly, They relate to 6 subduing the inoculated pustule, as soon as it has sufficiently produced its influence on the constitution.'

The necessity of a farther statement of facts, relating to the 1st head, appears from the accounts given of persons taking the small-pox, who had previously undergone the Var. Vac. On these cases,' says the author, I shall for the present suspend any particular remarks, but hope that the general observations I have to offer in the sequel will prove of sufficient. weight to render the idea of their ever having had existence, but as cases of spurious cow-pox, extremely doubtful.' Dr. J. next enumerates the sources of a spurious cow-pox. Ist, That arising from pustules on the nipples or udder of the cow; which pustules contain no specific virus.

2dly, From matter (although originally possessing the specific virus) which has suffered a decomposition, either from putrefaction or from any other cause less obvious to the senses.

3dly, From matter taken from an ulcer in an advanced stage, which ulcer arose from a true cow-pox.

ct

4thly, From matter produced on the human skin from contact c with some peculiar morbid matter generated by a horse.'

The terms of the 2d proposition are hypothetical, and the distinction between the 2d and 3d is sufficiently obscure but the reader may expect the elucidation in the commentary on them.

Concerning the first source of disease above mentioned, Dr. J. tells us that the udders and nipples are subject to a variety of eruptions, and that many of them are capable of giving a disease to the human body different from the true cow-pox: but, after having raised these doubts, and recommended a suspension of all opinion as to what is and what is not the real cow-pox, we get no satisfactory information from the author. Indeed, according to our apprehension, the distinctions pointed out are vague, and perhaps merely hypothetical. A case in point is thus stated:Sarah Merlin milked a cow whose nipples were affected with large white blisters: the girl's hands became affected in like manner with blisters, and inflammation, but no constitutional indisposition followed: this dis

order being considered as the variola vaccina, the patient was

thought to be secure from the small-pox: but she afterwards I

took this disease, and had a full burthen. Now,' says the author, had any one, conversant with the habits of this disease, heard this history, they (he) would have had no hesitation in pronouncing it a case of spurious cow-pox; considering its deviation in the numerous blisters which appeared on the girl's hand; their termination without ulceration, its not proving more generally contagious at the farm, either among the cattle or those employed in milking: and considering also that the patient felt no general indisposition, although there was so great a number of vesicles.' We will venture to affirm, from the accounts of the cow-pox published in the current year, that these observations do not distinguish that complaint from other similar diseases.

With respect to the 2d source of diseases resembling the cow-pox:-instances are related of persons having, by inocu lation with variolous matter, an inflammation, pustules, pains in the axillæ, and fever at the usual time, yet they afterward took the small-pox; and these failures were imputed to the state of the variolous matter used in the inoculation. After this, ought we,' says the Doctor, to be in the smallest degree surprized to find, among a great number of individuals, who by living in dairies have been casually exposed to the cow-pox virus, when in a state analogous to that of the small-pos above described, some who may have had the disease so imperfectly as not to render them secure from variolous attacks?" Thus, then, from analogy only, it is concluded that spurious cases of cow-pox occur from the altered state of the real matter of this disease.

Concerning the 3d source of diseases liable to be confounded with the var. vac., not a single evidence from practice is adduced: but the author shall speak for himself:

I shall observe that, when this pustule has degenerated into an ulcer, (to which state it is often disposed to pass unless timely checked,) I suspect that matter possessing very different properties may sooner or later be produced; and although it may have passed that stage wherein the specific properties of the matter secreted are no longer present in it, yet, when applied to a sore (as in the casual way) it might dispose that sore to ulcerate, and from its irritation the system would probably become affected; and thus, by assuming some of its strongest characters, it would imitate the genuine cowpox.'

We next come to the 4th origin of diseases; and here it is maintained that the cow-pox is derived from the horse. We do not think it necessary to state the reasons for this opinion

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as given by the author, because they amount to no more than presumptive evidence; and even this has been refuted by other evidence of the same kind, or in part by direct contrary proof from inoculation with the matter of grease,-from the absence of the cow-pox where the grease prevails,-and from the prevalence of it where no such disease as the grease was present. As, in our account of Dr. Jenner's former work, we expressed our disapprobation of the conclusion that grease was the origin of the cow-pox, and he still persists in the opinion, but without any additional evidence, we must now take the liberty of saying, that the credit of neither the present nor the former work would have been lessened by the omission of the unsound reasoning on this topic,

By way of preparation for the practice with escharotics and caustics, the following observations are delivered:

• From the very slight indisposition which ensues in cases of inoculation, where the pustule after affecting the constitution quickly runs into a scab spontaneously, or is artificially suppressed by some proper application, I am induced to believe that the violence of the symptoms may be ascribed to the inflammation and irritation of the ulcers, and that the constitutional symptoms which appear during the presence of the sore while it assumes the character of a pustule only are felt but in a very trifling degree. This mild affection of the system happens when the disease makes but a slight local impression on those who have been accidentally infected by cows; and, as far as I have seen, it has uniformly happened among those who have been inoculated, when a pustule only, and no great degree of inflammation, or any ulceration, has taken place from the inoculation.'

Dr. Jenner next relates two instances of the variola vaccina, in which, on the 14th day, an inflammatory appearance taking place around the inoculated part, ointment was applied, consisting of unguentum hydrargyri nitrati, and plaister of ung. bydrargyri fort., and in two or three days the virus seemed to be subdued.' As, however, the practice with these applications does not appear to be necessary, we shall suspend our opinion, till we have heard the reports which may be expected from others who have very extensively practised the vaccine inoculation.-At the close of the pamphlet, are inserted some communications to shew that the cow-pox is a perfectly safe disease, even to infants: one only twenty hours old' having gone through it without apparent illness; yet it was found effectually to resist the action of variolous matter with which it was subsequently inoculated.'

Although the present work does not contain matter of such interest, and which gives such satisfaction, as many parts of Dr. Jenner's former publication afforded, we shall always be

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happy