IN conversation with lepra specialists in countries where leprosy is endemic, nothing is more common than the admission that the alleged exciting causes of the disease, such as contagion, heredity, or malaria, are quite inadequate to account for the rapid progress of leprosy over a wide area in recent years. Dr. Alzevedo Lima, chief medical officer of the hospital, Rio de Janeiro, observes:—" Even at the present time, in spite of the progress in sanitation, and the more favourable conditions of life among the Brazilians, there are still centres of contagion, whence we receive patients for the hospital in larger numbers than from other places. Throughout the whole country, in fact, this terrible disease is still rife. This being so, if we consider the differences in climate, the food, the habits of life, the sanitary conditions, etc., of the various regions of this vast country, it is difficult to believe that the etiological factors still given as determining causes of the disease can be in themselves a sufficient explanation. At the most, they can only act as favouring conditions, and explain the greater or less frequency of the malady, its predilection for certain places or for certain classes of the people."—Journal of the Leprosy lnvestigation Committee, December 1891, p24

Alluding to this subject, Dr. Alzevedo Lima, writing to me from Rio de Janeiro, May 20th, 1892, says :— "None of the ordinary etiological factors explains satisfactorily the spread of leprosy in this country, where one finds focuses in places altogether different in the climate-telluric conditions, and where, besides the sick people who live in bad conditions of feeding, etc., there are many others who live in luxury and belong and dwell amongst the best society. The inheritance also does not account for it in a very large scale. About this last point I always take very great care to inquire of the sick people who are taken to the Hospital dos Lazaros, where we have had 242 patients during these fourteen years past that it has been under my direction. . . ." Referring to the inoculation of leprosy by means of vaccine virus, Dr. Lima says :—" I believe in the possibility of the fact, not seldom, and I suspect this may have been. the cause of the spread of the disease amongst our people, specially in the country, where, with the absence of a doctor, the vaccination is done by someone not professional, and therefore incapable of distinguishing whether they are using the vaccine taken from a pure source or not. Moreover, to those who know how long it takes for the incubation of leprosy, and how difficult it is to diagnose it in its initial stages and in several of its forms and varieties, it is easy to know that even the professional man may have given rise to the spread of the disease in that way.

"Amongst 62 persons affected with this disease now in treatment in the Hospital dos Lazaros, in this city, 26 were vaccinated, being 8 in Rio de Janeiro, 8 in the State of St. Paul, 6 in the State of Minas, and 2 in Portugal; the remaining 36 have never been vaccinated. Abstracting the 10 of Rio de Janeiro, where the vaccination is gone through with every care and the vaccine taken directly from the cow, we have 8 come from St. Paul, either from the. country or from small villages where the vaccination is performed, as a rule, by people not competent, and with the lymph taken at random from any person amongst their own people, where leprosy prevails endemically. In any of these States, in the absence of a physician, any clever man undertakes the duty of vaccinating amongst the people, and this may very likely be one way of propagating the leprosy."

Dr. Alexander Abercromby, of Cape Colony, referring to the causation of leprosy, says :—"It is evidently dependent on some vitiated state of the blood, and that acquired in many instances, as has been clearly ascertained, by hereditary predisposition. In many cases, however, it occurs where no such predisposition can be traced, and in persons whose parents were perfectly healthy, and who evinced during their lives no trace of the disease whatever. In these cases we are led, therefore, to seek for other causes to account for it."— Thesis on Tubercular Leprosy, p. 15.

In the Report on the Annual Returns of the Civic Hospitals and Dispensaries in Madras for i888, p. 14, under the head of Vizagapatam, Surgeon-Major Sturmer says that leprosy is on the increase in the district, and observes :—" This year I have seen many fresh cases of leprosy in adults as well as in children, in whom no hereditary taint could be traced. They evidently had contracted the disease from some outside source, for in each case it was ascertained that no other member of the family was affected."

The "Report on Leprosy in New South Wales," May 13th, 1891, forcibly exhibits the unsatisfactory condition of modern inquiry into the etiology of the disease. No mention is made as to the chief factor of causation.

The Secretary of the Board of Health in New South Wales, Mr. Henry Sager, observes :—" The detailed history of the cases given in Appendix C.,though of very considerable interest, does not furnish any grounds for definite conclusions as to the causation and spread of the disease. There are no data on which to advance a view of spontaneous, climatic, dietetic, mal-hygienic, or hereditary origin of the malady, and nothing of scientific accuracy to be adduced as to contagion, though the evidence in several cases points more or less strongly in this direction."—Journal of the Leprosy Investigation Committee, No.4, December, 1891, p.50.

The Report of the Inspector of Asylums for 1890, presented to both Houses of Parliament, Cape of Good Hope, under the head of "Female Leper Wards," p. 32, says :—" The fact which stands out most prominently in making these records is the absence of any history of direct contagion, or even with contact of a known source of the disease in almost all of the cases which have been investigated."

When, about a year later, Dr. S. P. Impey, the present medical superintendent of the asylum, Robben Island, unable to account for the spread of leprosy by popular medical theories, began a more careful and exhaustive investigation than his predecessors had ventured upon, and included vaccination, hitherto ignored, as one of the possible factors, he had no difficulty in tracing a number of cases directly to this source. Dr. Impey felt it his duty to warn the Government of this danger.

In concluding a second paper on "Notes on Acquired leprosy as observed in England," by Mr. Jonathan Hutchinson, in the British Medical Journal, July 6, 1889, this distinguished pathologist observes :—

"The twelve cases which I have quoted do not, I believe, comprise by any means all the examples of leprosy beginning in patients of British birth and descent which have come under my observation. They are all, however, of which I am able at present to find record in my note-books. One and the same criticism may be said to apply to all. They are the examples of the acquisition of a specific disease by healthy persons who had no inherited predisposition. In no single instance had the person so acquiring it been exposed to any degree of hardship, or deviated in any definite manner from the ordinary conditions of a cleanly and well-regulated life. In every case the acquisition of the disease had occurred in some country where it was known to be prevalent, the East and the West Indies being the chief localities. I submit—as, indeed, I have already suggested—that there are only two suppositions open to us by which to explain the de novo acquisition of such a disease in cases such as these. The patients must either have received the specific contagion of leprosy on some part of the skin or mucous membrane, or they must have swallowed it in connection with food. Both these suppositions are possible. I may confess, however, that to my own mind one of them seems far more probable than the other. In no single instance had there been any known exposure to contagion. In no case had the patient associated with anyone suffering from leprosy, and in most instances the statement given was that they had but rarely seen lepers, and had certainly never come near them."

Amongst the possible sources of leprous contamination, Mr. Hutchinson, while inclining to what is known as "the fish theory," mentions "the perils of vaccination."