These facts have a very important bearing on the question of the propagation of the fever. They show that out of 156 men, taken indiscriminately from the different rooms, very few of whom could have had yellow fever before, and who afford 210 instances of exposure for twenty-four hours to the emanations from the sick in the fever wards, that only 8 were subsequently affected with fever of any sort, of whom 3 died; while, from the remainder of the troops in the cantonment, amounting, at the commencement of the epidemic, to 523, there were 89 attacked with fever, of whom 38 died. Putting those numbers into the form of a centesimal ratio for the sake of comparison, they stand:

These numbers most fully warrant the conclusion that exposure to the effluvia from the sick was not an active cause in propagating the yellow fever at Newcastle in 1856; and if it be considered that of the eight men who attended on sick and were subsequently themselves attacked, four presented none of the prominent characters of yellow fever, while of the four who did, three came from rooms in which persons had previously been attacked with decided yellow fever, without communication with sick, so far as is known, there is no alternative but to limit the conclusion in these cases still more, by excluding the operation of specific contagion altogether.

The following conclusions seem fairly deducible from the preceding details. To render them clearer, the principal facts have been

appended:

1st. That yellow fever prevailed at Newcastle, in 1856, in welldefined zones, alternating with others which presented a much smaller amount, and, for the most part, a different form of fever, attended with a much smaller mortality. These zones embrace:

A. Officers' quarters above mess-room and race-course encampment (including last two cases at race-course, the others being referrible to A room)

B. The buildings between the mess-room and parade-ground, including officers' quarters, hospital, A and B rooms, bakery, cells, and all tents and huts in the neighbourhood (excluding first six cases in hospital as referrible to low ground, and the last as indeterminate).

C. Rooms C to F inclusive

E. Rooms I to N inclusive

Cases.

2

430

Deaths.

...

. 0

31*

60*

D. Rooms G and H inclusive

13

19

10

* If the cases which occurred in the officers' quarters be set aside, as of doubtful origin, these numbers will be, cases 54, deaths 28, presenting exactly the same characters for a more limited locality.

2

5

In consequence of the frequent changes which took place, it would be very difficult to ascertain the mean number exposed in these localities; and the persons being exposed at different periods of the epidemic, the resulting ratios of attacks and deaths would not be strictly comparable. The rooms from F to N, however, were occupied during the whole course of the disease by soldiers, and as each room contained on the average thirty-four men, the comparative progress of the fever in these may be determined with tolerable accuracy.

These ratios show conclusively that the causes of fever operated with much greater intensity in some localities than in others, and that these unhealthy spots were distinctly circumscribed. It is questionable how far the three deaths in the rooms from I to N were due to these localities, one of the men having been permanently engaged on the public works, and the other two having been on the main-guard (which brought them into an unhealthy locality), one nine days and the other six days, before his attack; were these cases produced by exposure on guard, the healthiness of these rooms would appear still greater.

2nd. That bodies of men moving from an unhealthy to a healthy locality soon lost the disease, though they carried most of their bedding and their clothing with them; and, in the healthy spots, did not communicate the disease to others who were from other healthy spots.

The light company moved from A and C rooms to the race-course, about October 24th; four of them, from A room, were attacked up to the 30th (one of them decided yellow fever), but no man from C room was attacked. On December 7th, a woman and child were removed from near A room to the race-course; the child had decided yellow fever, and a week after the woman was attacked, but the disease stopped with them.

After the removal of the hospital to C and D rooms, no patient except Needham, or permanent hospital attendant except the cook, who had not been in the regular hospital, was attacked with fever. Previous to this removal, and immediately after it, several hospital attendants and patients suffered from the disease in its most aggravated form, but all had been exposed to the morbific influences in the first situation.

The married people and their families were removed from B room on October 21st, and distributed in various places. Three cases occurred within the next two days, but then the disease ceased among them, except in one woman, who went to the shoemakers' shop to reside itself an unhealthy locality.

On November 11th, two companies were removed from F, G, and H rooms to the farm, and carried most of their bedding with them, yet the aggravated form of fever did not continue among them.

3rd. Persons going from healthy to unhealthy localities to reside, caught the disease.

The Band removed from E room (where they had been quite healthy) on October 29th, to the upper two plateaus below M and N rooms, where fever appeared among them; and there are many instances in which people went to the cells, or went to the hospital, from healthy localities detailed above, in which they were soon after affected with the disease in an aggravated form. An argument will undoubtedly be advanced here by some, that the Band having occupied E room previous to removal, were within reach of the contagion from D room, then the fever ward. This is met by the fact that the first case in this locality was that of Private Boyle, who lived here before the arrival of the Band, and did not belong to it, and had not been near the sick, so far as is known. Boyle came sick on November 2nd, and Tuer, the first of the Band, on the 4th, though he seems to have been unwell a day or two before. Both died of decided yellow fever. The fact stated above, too, of those who actually attended the sick suffering much less than those who did not, is adverse to the idea of the Band having been affected by contagion previous to removal.

After the removal of the men from F, G, and H rooms, on November 11th, F and G were occupied by men who, up to that time, had been in I and F rooms; and fever appeared among those in G in December.

4th. The activity of the causes of the fever seems to have been much diminished by a course of wet weather commencing on November 4th, accompanied by a severe storm, and heavy rain on the 6th and 7th; and yellow fever disappeared after December 21st, on the accession of strong cool northerly winds.

The admissions from fever of every description in November and December were as follows:

5th. The disease showed itself in its most malignant form in persons who had not been away from Newcastle for many months, and who were not exposed to others previously affected with it, or to their clothes, or other media usually considered as likely to convey contagion.

The last case of yellow fever.

The cases of Private Monk in A room, on September 21st, and of Mrs. Bell in B room, on the 22nd; and again, Private Leather, on October 12th, from the cells, are clear instances of this.

An additional proof of the possibility of such an occurrence is given by the appearance and progress of the fever in the family of the schoolmaster-serjeant of the 97th, as recorded by Dr. McIlree, in 1848, noticed above.

6th. Persons in contact with sick in a healthy locality did not contract the disease more frequently, or indeed as frequently, as those in barracks.

The list of the men who attended the sick of fever in hospital shows that of 156 who were so employed, giving 210 separate instances of exposure for twenty-four hours to the emanations from the sick in the fever wards, only 8 were afterwards attacked with fever a smaller proportion than among those in barracks, though their exposure to contagion, were it existing, was of course infinitely greater.

Further, no hospital attendant, or patient, except Needham, who had not been in the hospital building, contracted fever after the sick were removed from it and the surrounding influences; though, had contagion been the exciting cause of the disease, there was as much or even more reason for the attendants becoming affected after the removal than before it; 32 of the 41 deaths of soldiers having occurred after the removal, and the ventilation of the rooms not being better than that of the hospital.

Taking these facts together-and in this argument they must be taken together, unless they can be shown to be unfounded-they appear utterly opposed to the view that the disease either arose from, or was propagated by, specific contagion.

That a cantonment of about 800 yards in length, on a narrow descending mountain ridge, should present four well-defined healthy zones, alternating with three others in which a disease supposed to be contagious prevailed, while the communication from one extremity to the other was free and unrestrained (save with those actually sick in hospital), is contrary to all experience, and of itself, were there no other evidence, would go far to overthrow the idea of specific contagion having acted; but with the additional weight of the evidence adduced above, this position seems quite untenable, and there is no alternative but to look for the explanation of such circumscribed effects to the influence of causes equally local in their operation.

The first unhealthy zone, noticed above, embraces the buildings between the mess-room and the parade-ground; by referring to the projection it will be seen that these follow the course of the ridge, pass on to the hospital, B room of the men's quarters, quartermaster's store, bakery, and cells, and form a sort of crescent round the head of a deep abrupt gully, which at its upper part runs nearly east and west. The valley may be said to have a southerly exposure, as the bounding height to the north is much higher than that to the south, a point that will be hereafter alluded to. On the western side of this zone,

A room, the tailors' and shoemakers' shop, and some huts are situated; these are immediately over the upper extremity of a watercourse, and a considerable gully, formed by a land-slip; both the watercourse and gully having a southwesterly exposure, and descending at an augle of about 40° below the horizon.

The next unhealthy zone comprises G and H rooms. As mentioned above, there is a high retaining wall supporting the bank behind these rooms, about eight feet from them, and as high as the eaves; about thirty feet from this space, and directly in a line with it, a gully commences, which drains that part of the barracks, and is so placed with regard to G room as to throw the current of air which ascends through it on the end of that room, and into the space between it and the wall at its back.

The last situation where the disease showed itself severely was on the upper two plateaus below the barracks, where it appeared after the disturbance of the ground in levelling, and the exposure of some decaying vegetable matter from cutting trenches to carry off the surface water. There is no gully or watercourse near these spots, such as those above mentioned.

There is a large gully on the east side of the barracks, beside the grave-yard, but it is wider than those just referred to; it is less steep, and from the form of the ground at the top, the ascending currents of air through it are not directed immediately on any of the buildings. That it was not perfectly innocuous may be inferred from the occurrence of two cases of yellow fever (one of which proved fatal) in persons living in the huts on its northern side. At all other points where the men remained healthy, though the ground of the ridge occupied by the buildings was narrow, the ground on either side of it sloped away gradually for a little distance before terminating in the steep descent of the mountain side; and there were no gullies or ravines opening near the houses, or the natural undulations of the ground had more or less of a northern exposure.

The valley terminating to the east of the hospital had its bottom and sides covered with the thick bush usually seen in such localities; this grew over its whole extent, from the lowest point in the plan almost to the road under the quartermaster's store; between this road and the store there was a quantity of old thatch, which had been pulled off the roof of the store, and thrown down there in June, 1856. This had been covered with earth, and it was not until going over the ground early in 1857, that, on examining the ruts cut in it by the water, the straw became apparent, and led to further examination, when it was found extending over an area of some thirty or forty yards.

The gullies to the west of the hill did not contain any bush; but there was a small quantity of open bush beyond them, on the side of the bill. A quantity of refuse-such as bones, ashes, pieces of cloth, &c.—had gradually accumulated over the slope and about the outlets. This was cleared away in the middle of October, and the men employed on the duty complained of the unpleasant odours evolved, but,