In Colorado, I will place the altitude of approximate immunity at 6000 feet. There are good grounds for this decision. I have made quite a thorough canvass of the subject among the physicians of the State, and have found but one case originating above this altitude, and that not very well authenticated-said to have been a case of catarrhal pneumonia of the right apex which afterward improved. Drs. T. G. Horn, of Colorado Springs, and G. S. McMurtrie, of Central, with others who have practised in the mountain districts for a considerable time, have reported that they could furnish no cases of the kind from their experience in Colorado. Between the elevations of 4000 and 6000 feet, however, I have found a few cases. There have been twenty-two in all up to the present date, occurring in the practice of physicians who have most of them resided in Colorado several years. Let us analyze these cases, and learn that it is greatly due to the looseness of the general term phthisis that most of them come under this nomenclature.

Dr. H. O. Dodge, of Boulder, reports four cases from that section; two of the patients have died, and two are not losing ground rapidly; all of these cases commenced with severe colds from exposure; three of the patients probably had pneumonia, and one suppression of menses, which has since continued: time they had lived in Colorado not stated. Dr. Joseph Anderson, of Golden, reports a case of general tuberculosis following miscarriage, rapid decline, and death in four months. Also a doubtful case of abscess following pneumonia in a young man whose father died of phthisis, and which has resulted in apparent recovery. Dr. Jacob Reed, Jr., of Colorado Springs, reports a case in a young man aged 18, three years a resident of Colorado, and with very marked tendency to phthisis by inheritance. Had had slight cough five months when he received a severe injury to one lung, followed by hemorrhage and death in one month. Dr. H. B. Tuttle, of Puebla, has seen two cases "one a sequel to scarlatina, and one following extreme exposure during menstruation, both badly treated, both fatal."

For the city of Denver and immediate vicinity, we have the records of all the deaths occurring since January, 1874, two years and a quarter. These records require information as to the origin of the disease. We find thirteen cases recorded as originating in Colorado. They are of "phthisis," "phthisis scrofulosa," "acute phthisis supervening" as a sequel to other diseases, etc. I have interrogated most of the physicians who reported these cases, and find two acknowledged mistakes, in that the disease existed before the parties came to Colorado; two rapid cases of Cachexia Africana; two cases of rapid decline after child-birth; a child one month old, whose mother died of the same disease nine days later; a case of abscess in the base of the right lung following pneumonia; acute phthisis following pneumonia, and hip-joint disease; a case of "whiskey consumption"; a fatal result in a very strong man, after hemorrhage from severe lifting; and a case following scarlatina. Now I cannot see that elevation offers any special antagonism to such cases; and as to accidental lesions of the lung, causing hemorrhage, and also acute double pneumonia, the mechanical influence of rarefied air cannot for the time be considered otherwise than injurious; while phthisis fol

A. T. ("Arizona as a Health Resort for Consumptives," Virginia Medical Monthly, December, 1874.); W. J. Wilson, Ft. Bayard, N. M.; Oscar A. Woodworth, Mesilla, N. M.; J. V. Lauderdale, formerly stationed at Tucson, Arizona, and C. B. White, Fort Independence, California.

lowing scarlet fever is not to be wondered at, in that the convalescence from special fevers is generally noticed to be tedious in the Rocky Mountain regions.1

An additional evidence in favor of an approximate immunity due to elevation may, I think, be gained from the low rate of mortality from pneumonia, as well as from phthisis, as shown by our census statistics, especially as we are coming so generally to consider phthisis as of inflammatory origin; it is that while high altitude increases the unfavorableness of the prognosis of acute pneumonia, the ratio of deaths from the disease in the Rocky Mountain states and territories is greatly lessened, showing that there must have been few cases of pneumonia there to have passed into chronic disease.

EXPERIENCE.

The crowning argument in favor of high altitudes should be the carefully recorded results of the extended sojourn in elevated climates of a good number of consumptives, representing the various types and stages of the disease. In presenting the following table of the records of such of my cases as have been kept under observation more than two or three months during my three years' practice in Denver, it seems to me the shortness of the time is greatly compensated for by only recording the results during the patients' stay in Colorado. It is to be noted that the results, after patients left the high altitude, were generally unfavorable. Those patients who had to be sent away immediately, and those who were not kept under observation two or more months, are excluded from the table, which includes all the other uncomplicated cases of phthisis I have recorded. Three only of the patients had been in Colorado longer than three years, the time of observation specified, while six were in the State the shortest time, namely two months. The period of sickness previous to coming to Colorado, dating back to a persistent cough, pulmonary hemorrhage, hæmoptysis, or evident cause, varied from two months to seven years. Some had resorted to other climates (low altitudes) without benefit. Quite the usual amount of inheritance, in some cases the most decided in my experience, existed in these cases.

Almost all types of phthisis are included, the classification as to the Nature of Disease being quite general, and only of account as indicating the usually more favorable prognosis for inflammatory than for chronic tuberculous cases. As to the Stage of Disease, I have endeavored to make close diagnoses, and may have put some cases in the third stage which other physicians would have placed in the second. However, the second stage, in my opinion, does not amount to much in high altitudes, and for practical purposes may as well be considered with the third. If lung tissue has become useless, and "softening" commenced, "excavation" is not far off, with the expansion of the lungs due to elevation. That such a transition is necessarily a part of the high altitude treatment in consumptives so far advanced, will not appear strange to the reflective mind; though its expediency in some acute cases may well be

I have known a case of catarrhal and another of chronic pneumonia, contracted in Denver, in negroes who subsequently recovered, but who would undoubtedly have died from phthisis had they been sick in the East.

doubted. This positive character of the rarefied air prescription leads me to differ as to part of Dr. C. T. Williams's classification. I refer particularly to the "stationary" cases which include a good number of his patients. With the healthful respiratory quickening of high altitudes, the lungs are either not equal to the strain, or they improve under the exercise. I prefer to designate the apparently "stationary" cases of advanced phthisis by what sometimes occurs in them, namely, an extension of excavation, while the resistance of the system to the general effects of the disease is favored by the healthful surrounding influences. As to whether this table represents the average severity of the phthisical patients who seek relief in Colorado, there is a pro and con to the question, with a preponderance of evidence in favor of its representing more than the average severity. Invalids whose disease is uncomplicated, and with whom the benefit is immediate and continuous, after their arrival in Colorado, do not, generally, consult physicians there. A proportion of such cases, including many I know to have improved, but of which I have no record of examination, are, of course, not included in the accompanying table. For instance, in the Pullman car in which I left Denver, to come to this Congress, there were four returning health-seekers-three ladies and one gentleman-three of whom went to Colorado in the first stage of phthisis, and the other in the second or third; all of them apparently now enjoy a complete arrest of the disease, and none of them employed a physician in Colorado. On the other hand, a few months after my arrival in Colorado, I wrote an article discouraging the sending there of consumptives with unfavorable complications, after the stage of softening, those affected with heart lesions, etc.,' and I am pleased to say that my professional friends in the States have seldom recommended such cases to me. However, the cases are severe enough taken as they are, and I am agreeably surprised with the progress of several having more or less excavation.

'Chicago Medical Examiner, January 15, 1874.

TABLE VI.-Phthisis in Colorado.

Analysis of 69 years, 2 months, spent by 66 consumptives in Colorado, with results.

Of these analyses, that in reference to the stage of the disease is first and most important. The twenty-five first stage cases were 38 per cent. of the whole, and they averaged over a year and a third under observation in Colorado. Of these, 68 per cent. (17) were much improved or cured, 28 per cent. (7) gained slight improvement, and 4 per cent. (1) died. Of the one unfavorable case, an explanation is needed. A beautiful young lady, age twenty, came to Denver in July, 1875, having chronic laryngeal phthisis with complete aphonia, which had been coming on two and a half years; loss of weight, strength, and appetite, increased of late. Dyspnoea increased, and catamenia absent three months. Grandfather, father, brother, and aunt and uncle, died of consumption, and brothers and sisters living, not strong. Dullness with pleuritic adhesions at base of right lung, and deposit, which I believed to be of true tubercle, at left apex. Slight improvement during the fall. Afterwards she went to live on a ranche, by my advice, with instructions not to mind the loss of voice, but to gain in general strength. Gained seven pounds in two or three months. In February, she followed the meddlesome advice of somebody, and submitted to "throat treatment" from a man who claimed to be a physician, in a neighboring town. The local application of a sixty grain solution of nitrate of silver was a sample of the treatment under which this delicate creature lost thirteen pounds in less than a month. In two months more she died of acute phthisis. I regret exceedingly to have my list marred by such malpractice. Sixty per cent. (15) of these cases are now living in Colorado.

The cases of the second and third stages include a variety, the second embracing several acute, and the third some extremely chronic or prolonged third stage cases. Of the 17 per cent. (11 patients) who were in the second stage, averaging one year under observation, 18 per cent. (2) were much improved; 36 per cent. (4) slightly improved; 18 per cent. (2) had slight local extension, with general tolerance of the disease; in 18 per cent. (2) the disease extended and advanced; and 9 per cent. (1) died in Colorado-or 73 per cent. (8) improved or tolerated the disease, and 27 per cent. (3) became worse or died. Of the 45 per cent. (30 patients) who came to Colorado in the third stage, averaging nine and a half months under observation, 17 per cent. (5) were much improved, 17 per cent. (5) slightly improved, 27 per cent. (8) had slight local extension with general tolerance of disease; in 33 per cent. (10) there was extension and advance, and 7 per cent. (2) died in Colorado-or 60 per cent. (18) improved or disease tolerated, and 40 per cent. (12) worse or died. Of the whole sixty-six patients, 17 per cent. (11) were lost sight of after they had been under observation two or more months; 37 per cent. (24) were much improved; (24) per cent. (16) slightly improved; 15 per cent. (10) experienced slight local extension but tolerated the disease. In 18 per cent. (12), there was extension and advance; and 6 per cent. (4) died in Colorado-or 76 per cent. (50) improved and tolerated the disease; 24 per cent. (16) became worse or died; 48.5 per cent. (32) now reside in Colorado. Thus is shown by evidence, which is abundantly conclusive, the salutary influence of the elevated plains in Colorado upon phthisisa disease eminently progressive in character. Thus too is shown, what those who live in Colorado have all along believed, namely, that the first or primary stage is pre-eminently the remedial period for high altitudes.

As to age, we find 4 per cent. (3 patients) under 20 years old when they came to Colorado, of whom one was the most remarkable example