To those interested in this question (and what general practitioner is not?), it is well for me to state that I have followed up the same practice with the like favorable results. Since my article was published in the Edin. Med. Journ.' in 1861, I have delivered with the forceps as usual, and have had no deaths in these cases, and in the whole practice, under my own care, since then, with one exception, a footling case, all the children have been born alive.

I am, Sir, yours, &c., G. HAMILTON, M.D.

We extremely regret that Dr. Hamilton conceives us to have misrepresented his views. Any one taking the trouble of referring to our article will see that we were specially desirous of approving Dr. Hamilton's practice, and of giving him due credit for arriving at a rate of foetal mortality which he justly calls "altogether unprecedented." We say, "Dr. Hamilton recommends us to use the forceps within a quarter of an hour after an ear can be felt if no progress is being made." In his present letter Dr. Hamilton says, "When mother or child seem much exhausted by a protracted or very severe labour my rule is, when an ear comes within reach, not to wait more than a quarter or half an hour." The omission of the qualifying clause is to be regretted, since it materially modifies the rule, and is due to the fact that we were writing from our recollection of Dr. Hamilton's paper, which we had not at hand at the moment. The object of the succeeding sentence, the meaning of which Dr. Hamilton cannot understand, and which no doubt might have been more clearly worded, is evidently to contrast Dr. Hamilton's practice favorably with that of those who wait two or more hours after an ear can be felt, and even then do not interfere as long as there is any hope of the unassisted pains completing the delivery, however long that might take.

In our article we have very distinctly stated that we consider Dr. Hamilton's views to be right, and we fail to see that we have done him any injustice.

Reclamation of Dr. Murray.

[WE willingly give insertion to the following reclamation of Inspector-General Dr. Murray, in respect of our notice of his report on cholera in our number for July last, p. 171. His long Indian experience, and his high position in the medical department of Bengal, justly entitle his remarks to respectful consideration. Among other points we took exception to the evidence, as being quite insufficient, on which he rested the proposition that "there are numerous well-authenticated cases of the poison (of cholera) having been mixed with the water of wells and tanks, those using the water being attacked by the disease." The two cases cited by Dr. Murray are the only instances adduced out of the replies of 500 medical officers who responded to his queries. It is, moreover, to be observed that there seem to have been no replies whatever to the question as

to "the effects of admixture (in water) of evacuations from affected individuals," nor yet to another which asks for information respecting "the dissemination of the disease through the evacuations of those affected." We attach the more importance to what seems to us as extremely meagre evidence upon a point relating to the causation and diffusion of cholera outbreaks, in consequence of the high favour which the water-propagation theory of the disease has inet with from some of our leading sanitary authorities of late years. When such men as Farr, Simon, and Jenner, in this country, and Murray, Macnamara, and others in India have accepted it, it is only but right that we exact clear and unmistakable proof of a doctrine so highly patronised. The profession looks for much stronger evidence than has yet been adduced before they can generally accept it as a verity. Dr. Murray would do a great service if, from the ample means of information at his command, he would collect and make public all the well-authenticated evidence from Indian experience bearing on the subject.

On the other point to which he refers, viz., that the outbreak and diffusion of cholera are mainly due to human intercourse, as "proved by the history of the progress of the epidemic attacks in India, Europe, and America," we still maintain that the proposition is far from "having been proved." He confidently declares, in his official letter to the Government at the end of 1869, that "the question of the communicability of the disease was set at rest, as far as any medical question can be settled, by the opinion of 99 per cent. of the medical officers in India, as shown in (Table) No. VII of my report on the treatment of cholera." On referring to that table it will be observed that under the general term of "communicability," Dr. Murray includes five different channels or media by which the poison of the disease may be transmitted or conveyed; these are, "from person," "from place," "by atmosphere," "by water," through evacuation." Are we to understand by this classification that cholera is propagable not only by personal communication with the sick, but also by visiting sickly localities, as well as by atmospheric infection and by water communication? On these points we must ask for much more exact testimony than we have been able to find in the documentary evidence appended to Dr. Murray's report. We should like, too, to learn, among other subjects, what have been the results of his experience as to the comparative number of attacks among the medical and other attendants in Indian hospitals, and among the general community.1]

1 After these remarks had been written we saw the report of the Sanitary Commissioner with the Government of India, for 1869, recently issued. In respect of the great epidemic of that year in the Bengal and Bombay presidencies, "the evidence," Dr. Cunningham says, "does not show that cholera was spread over the country by human intercourse;" and as to the opinion that its spread was due to water tainted with cholera discharges, he declares that "there is no evi

To the Editor of the British and Foreign Medico-Chirurgical Review. SIR, In reviewing my report on the treatment of cholera, and in reference to my views on the communicability of the disease through the medium of water, it is remarked, p. 171, "No detailed evidence for these vague statements is recorded." On this point there was no intentional ambiguity in the body of the report, and no want of illustration in Appendix II. In the extracts from the Reports under Query 12, the two following, which had previously been submitted to Government in my report on the Hurdwar epidemic of 1867, are those alluded to by the reviewer:-"A pilgrim was taken ill of cholera at noon on the 28th April, 1867, at a well in the village of Joogh Kullan, and he died next day. His soiled clothes were washed in an adjacent pond. Other parties who afterwards visited the well and the pond for water and ablution, caught the infection. The disease broke out on the 30th, and up to the 15th May fiftythree were attacked, of whom twenty-seven died." "At the village of Besubat two men who had returned from the Hurdwar fair died of cholera on the 30th April, 1867, and their clothes were not burned according to orders given, but were washed in a pond which was inside the village, the water of which was used for domestic purposes. On the 1st and 2nd May in the same village sixteen attacks occurred." It may be said that such reports are merely opinions in reference to the appearance of the disease, and that it was a mere coincidence in the time of the two events; such language may be used in reference to the dissemination of all diseases. In a case depending on circumstantial evidence, an opinion founded on the facts observed by one individual has little weight, unless in connection with that of others, when it may supply a missing link in the chain of evidence. Here lies the great value of numerous and detailed opinions. Individual experience is defective in different links; a statement which is invaluable in supplying a defect to one, may only be a repetition of former information to another whose doubts referred to a different portion of the chain. That may appear a trifling incident to one which may supply the missing link, or keystone, to another more experienced investigator whose opinion thus confirmed is valuable. The opinions of intelligent men may be considered as the result of evidence collected from different sources, as well as that obtained in their own individual experience of facts. A careful observer learns more from watching a succession of epidemics than from all the books that have been printed; but the observation of the disease as it appears in the hospitals of a large city, and limited to one epidemic, must be partial and very imperfect.

I am far from supposing that each opinion is of equal value, dence of any such contamination in the general history of the epidemic over the country." This report is a highly instructive document, and its value is enhanced by an elaborate communication from Dr. Bryden on the epidemic of 1869, and by one from Dr. Lewis on the Microscopy of Cholera Evacuations.

93-XLVII.

15

even when equal opportunities have been afforded of observation. This is a source of uncertainty in the valuable statistical table No. VII, more especially where there is great diversity of opinion; but this cannot diminish the value of the result where the opinions are unanimous, or nearly so. Such an opinion is unequivocally expressed on some of the most important points of the disease. That cholera is communicable is the opinion of more than 500 educated men who have studied the history of the disease since its manifestation in 1817 up to the present day, and who have, in some instances, had opportunities of gaining experience for upwards of thirty years. It must be observed that there is a column in the table showing when the officer had had no opportunity of observing the point in question, or had not made up his mind regarding it. These votes should be eliminated, but they are of great value in showing the conscientiousness with which the votes are given, as no one willingly confesses ignorance. The value of this table cannot be over-estimated in determining the important question of the communicability of cholera. On this single question, out of 505 opinions there are 478 affirmative and only 5 negative. There is a slight variety of opinion in reference to the individual method of transmission; but on thirty questions bearing on this point, including 15,150 votes, 13,817 are affirmative, or 91.20 per cent.; 1,107 are doubtful, or 7.31 per cent.; and only 222 are negative, or 1.49 per cent.

The investigation by the Indian Government has thus settled the question of communicability in the opinion of the medical profession of India. It is to be hoped the Governments in Europe and America will obtain a similar expression of opinion from the medical profession in other countries.

The opinions elicited in this report on all important sanitary questions are very generally in accord. There is no doubt that imperfect sanitary arrangements aggravate the severity and prolong the duration of attacks. The uncertainty is seen when the question leaves the sanitary and advances to the medical period, and it should then be treated as a medical subject. There is a peculiarity in relating facts when coloured glasses are unconsciously used to view them. This tendency to look at cholera through sanitary spectacles has proved a powerful lever to advance sanitary measures, but it has naturally distracted attention from the more essential object now under discussion, the disease of cholera, and it appears doubtful if the sanitary commission in London is better suited, either by locality or composition, to conduct an inquiry of this nature than a medical commission in India. The unanimity of opinion on sanitary points shown in Table VII, would indicate that full information has been already collected, and is available for medical investigation.

CALCUTTA, 10th September, 1870

JOHN MURRAY, Inspector-General of Hospitals.

Chronicle of Medical Science.

CHRONICLE OF PHYSIOLOGY.

By HENRY POWER, F.R.C.S., M.B. Lond.,

Senior Ophthalmic Surgeon to, and Lecturer on Ophthalmic Diseases at, St. Bartholomew's Hospital.

BLOOD-CIRCULATION.

1. N. O. BERNSTEIN. On the Exchange of Gases between Arterial and Venous Blood. ('Berichte d. Sächs. Ges. d. Wiss. Math. Phys. Classe,' 1870, p. 124.)

2. SAMUEL HAUGHTON, F.R.S. On the Mechanical Work done by the Human Heart. (Dublin Quarterly Journal of Medical Science,' Feb. 1870.)

3. ANDREW BUCHANAN, M.D. On the Force of the Human Heart. ('Lancet,' Nov. 12, 1870.)

4. FRANZ RIEGEL. Essay on the Phenomena of the Circulation in the Smaller Vessels. (Centralblatt für die Medizinische Wissenschaften,' No. 29, 1870.)

1. Bernstein made diffusion experiments in Ludwig's laboratory with two test specimens of defibrinated blood taken from the same dog, of which one was arterial and from the carotid artery, the other taken from the carotid after the trachea had been tied, and which, consequently, resembled closely the blood of an asphyxiated animal. The septum was a thin membrane composed of a cæcum that had been purified by water and alcohol to remove all soluble materials, and thus to obviate any tendency to chemical change. From each chamber a quantity of the blood was taken at once for analysis, whilst a second portion was analysed after diffusion had continued for a period of from five to seven and a half hours. No noticeable passage of oxygen from the arterial into the venous blood occurred, but a small quantity of carbonic acid diffused from the venous into the arterial blood. The experiments were not numerous enough to admit of any deductions being drawn between them and the conditions present in the placenta.

2. Dr. Haughton estimates that the left ventricle of the human heart has a capacity, when in action, of 3 oz. or 5.2 cubic inches, and beats 75 times in a minute, whilst the value of the arterial pressure or the weight of the hæmostatic column is 9.923 feet of blood, which approximates that given by Donders (10-527 feet). From these data he proceeds to calculate in feet tons the daily work done by the left ventricle of the human heart, which lifts at each stroke three ounces through a height of 9·923 feet, and gives the value as follows: