the termination of the New York epidemic in 1822 is worthy of a moment's thought. He says the disease continued to spread till the 20th of September, when a very heavy rain occurred, followed by a cold, strong, northerly wind of two days' continuance. The effect produced on the progress of the fever was in a high degree sensible and striking; in four or five days (five being the supposed period of incubation), the cases diminished till the eighth, when not one was reported to the Board. The subsequent cases appear to have arisen from infection remaining in the houses, and not to have been acquired in the streets.' The occurrence of cases among persons who returned to New Orleans, after the disease of 1853 had ceased as an epidemic, is mentioned by Dr. Fenner. Such records are very common, though Dr. Walters' suggestion regarding the origin of these cases does not seem to have attracted much notice. Admit that the poison may be shut up and preserved in rooms and closets, and it is not much to concede that it may be imprisoned in boxes and in unventilated merchandise. The spread of the disease by fomites is not claimed to be among the most common modes of transporting it. But the question is not now how frequently it occurs, but does it occur at all? not whether it produces epidemics always or often, but does it cause a sacrifice of human life that may be prevented? Till this question can be convincingly answered in the negative, quarantines will at least serve to relieve an anxiety that is neither ignorant nor uninquiring. But if ships and their cargoes should be quarantined, is it necessary to detain persons? Certainly not, if the disease is not contagious, and this is the general and growing conviction. Their personal effects, however, till they are ventilated, should share the fortunes of the cargo. The garments worn upon the person appear rarely to have been charged with doing the office of fomites, perhaps because they are so freely exposed to purification. by the air.]

[Med. and Phys. Journ., vol. i. p. 477.]

CHAPTER V.

VARIETIES AND FORMS.

SEC. I.-Season and Locality. Yellow fever is not exempt from that very general law of pathology according to which endemic and epidemic diseases, especially, vary more or less widely in severity, and sometimes in other respects, in different periods, and in different localities. Sometimes and in some places the general character of the disease is mild and the mortality small, at others it is grave and malignant and the mortality excessive. The disease varies also in other respects, in different seasons and places, sometimes one element or tendency and sometimes another in its complex pathology predominating. Thus the prevailing character of the disease may be, during one season, simple and mild; during another, violent, and inflammatory; and during a third, adynamic and congestive. Similar differences have also been observed at dif ferent periods of the same epidemic, in a given locality. It is a common opinion, indeed, that the commencement of an epidemic is usually marked by greater malignancy and severity than its subsequent periods. The causes of these fluctuations and differences in the severity and character of the disease are wholly unknown to us; there are no obvious or appreciable influences to which we can attribute them; and in the absence of all positive knowledge upon the subject, we are obliged to refer them to unknown and hypothetical constitutions of the atmosphere, and to differences in the quantity or quality of the essential remote cause of the disease. It is proper to say here that, although there can be no doubt about the existence of these differences, still, their extent, degree, and frequency, have been less carefully studied, and less positively ascertained, than many other points in the natural history of this disease. There are, however, in addition to the general opinions of those who have been most extensively familiar with the disease, numerous well ascertained and authentic facts bearing upon the question before us.

SEC. II.-Forms, or Grades. Different writers upon yellow fever have divided the disease into forms, or varieties, more or less numerous, depending upon different degrees of severity, or upon the preponderance of certain groups of symptoms. The most common, and I think the most natural of these groupings, is that which makes three forms or varieties of the disease, to wit: First, the Simple or Mild form; Second, the Inflammatory form; Third, the Congestive, or Malignant form. This subdivision is of course to a certain extent arbitrary and conventional; still, it is founded in nature, and it is both useful and convenient, on many accounts, in the description and history of the disease. It corresponds very nearly to the similar divisions in other epidemic diseases;-to the simple, the anginose, and the malignant forms, for instance, of scarlet fever.

The simple or mild form of yellow fever is marked by the smaller number of symptoms than are present in the graver cases, and by their very moderate degree of severity. Most writers make particular mention of this variety of the disease; and it is very common during certain epidemics. Louis describes it in the following terms: "Most commonly, at the commencement, there were headache, chills followed by a slight degree of heat, pains in the limbs, and redness of the face and eyes. The epigastric pains were rare, and so too were the vomitings, which were almost never spontaneous, and which in no case were of a brownish color. The heat and thirst were moderate, and so slight was the diminution of strength, that the patients did not keep their beds at all, or were there for half a day only; thus, according to their expression, going through with the disease on foot. In this form of the disease, they were able to escape the vigilance of the health inspectors, resuming familiar occupations, or playing on musical instruments, when these last made their visits. In several of these cases, the febrile symp toms were very slight, continuing only during twenty-four or thirtysix hours." Dr. Lewis, of Mobile, says: "The attacks in the milder cases were occasionally so light and ephemeral, as to pass off in a few hours, leaving the patient with some soreness of the muscles, and slight pain in the hips and legs. But, as a general rule, they confined the patient to his bed for three or four days. After the chill, which was commonly of very short duration, the pain over the eyes, and in the back and hips, became for a short

Louis on Yellow Fever, p. 175.

time intense. The flushed face, animated voice, and sparkling eye, which characterized the febrile stage, have been aptly compared to the excitement produced by champagne. In a few days the disease has run its course, and after it has done so the patient is well; with a gentle perspiration, the momentary fretting of the nervous system passes rapidly away, without materially impairing or disturbing any of the organs." These mild cases occur most frequently amongst children, negroes, and natives, or those who have become more or less acclimated. During the prevalence of yellow fever at Gibraltar, in 1828, several persons, amongst whom were some of the medical practitioners, took pains to expose their children to the causes of the disease, in order to secure them against graver attacks later in life. Dr. Gillkrest says, in epidemics of ordinary severity, such mild cases may occur in the proportion of one to ten or twelve of the severer grades; and their occurrence will usually be found more frequent as the end of the epidemic season approaches.2

The open inflammatory form, as its name indicates, is characterized by the phenomena of frank febrile excitement. The local pains, especially those of the head, back, and limbs, are violent; the skin is warm, the pulse full and hard, and the thirst urgent. These symptoms continue for a day or two, and then gradually subside, giving place to convalescence; or they are followed by the stages of calm and collapse, terminating in death.

In the congestive or malignant form of yellow fever, the febrile excitement of the first period is either wanting, or only slightly marked; or, if present in any considerable degree, it is accompanied by certain phenomena indicative of the congestive element, and is soon followed by the gravest and most alarming symptoms of the disease. There seems to be a good deal of variety in the character of these cases. Sometimes the disease is in some degree latentits usual symptoms being either masked or absent. The walking cases, as they are called, belong to this variety. At other times, the disease is marked by a want of reaction, softness of the pulse, coldness of the surface, great restlessness and distress, a tendency to hemorrhage from different parts of the body, and rapid collapse.3

N. O. Med. Journ., vol. i. p. 295.

2 Cyc. Prac. Med., vol. ii. p. 270. 3 Dr. John Wilson divides the disease into inflammatory and congestive; he then makes three grades of the former-the mild, the violent, and the intense; and three

Some writers have gone much further than this, and have alleged that several distinct diseases, or forms of disease, have been con

of the latter; the slight, the aggravated, and the apoplectic. These varieties are thus described. "The most constant and prominent symptoms of the inflammatory were with, or without rigor, frequency and strength of pulse, wiry, compressed, or full; a hot, non-secreting condition of the skin, particularly at the præcordia, and across the forehead; headache, confined generally to the sinciput, with sense of fulness in the eyes, and tightness between the temples; jactitation, and constant rolling or otherwise moving of the head; flushing of face, with prominence, wildness, and sometimes inflammation of the eyes; pain in the back and loins, shooting across the anterior parietes of the abdomen involving the whole contents in tumult." With these symptoms there were also insatiable thirst; high-colored and scanty urine; and in some cases abdominal tension and tenderness in the early stages, followed by a sense of emptiness and exhaustion there as the disease proceeded.

In the intense form he says: "The action of the carotids was tremendous; the face red, and frenzied in expression: the eye sometimes clear, quick, and piercing; sometimes dull, and darkly inflamed, always indicative of great cerebral derangement. The skin had an intensity of heat scarcely conceivable, particularly on the breast, neck, and head. The tongue was parched, hot, and apparently diminished in size."

Of the congestive form he says: "A sense of stupor, weight, and oppression, rather than pain in the head; a feeling of helpless debility, affecting the spine, most distressing about the sacrum; a paralytic failure of the lower extremities, with pains in the knees and calves of the legs; a pulse having all degrees of celerity and expansion, but always weak, sinking under the finger without resistance; a state of the skin various and difficult to define, but always deficient in tone, sometimes dry and dense, sometimes greasy, and sometimes drenched in sweat; generally without increase of heat except at the præcordia, where it was confined and smouldering; a most distressing expression of countenance, deadly pale or livid in color; a drunken idiotic eye, with dilated pupil and sleepy motion; deafness; desire to be left alone; sighing, deep and interrupted; early tendency to coma; tension of the hypochondria, and early irritability of stomach, were the principal symptoms by which this division of the disease was characterized."

The highest grade of the congestive form is thus described: "The attack was like the effect of electricity. In an instant, its subject was seized with giddiness, dull pain of head, and confusion of ideas; a sense of coldness, weakness, and indescribable uneasiness along the spine; spasmodic pains in the legs, and paralytic incapacity of the lower extremities. He lay as if stunned, and laboring under concussion of the brain, with dilatation of the pupils, and a gloomy despairing countenance. The pulse was rapid or slow, full or small, but always weak. The skin was cold, generally greasy, or covered with cold liquid sweat, sometimes dry and lifeless."

"There is a modification of congestive fever so insidious as to give little alarm, and lead the inexperienced to think the patient is in no danger. The person laboring under this form of disease will confess, on being sharply questioned, that there are slight pain and heaviness in the head, and the epigastrium is tender on presOtherwise little appears to be the matter, the pulse being natural, or so nearly natural as to escape observation; the tongue clean; the skin cool or ob

sure.