"The past winter, a friend of mine had his gin house burned down, in which there was a great deal of cotton seed and cotton in the seed. This pile was burning for weeks. As his stock used in this yard, the ground which was prairie, became soft from the treading of the cattle; there being also a good deal of wet weather, it gave rise to a collection of water over the charred seed, which became peculiarly offensive both to the eye and olfactories; with myself it produced a paroxysm of sneezing.

"It was on the South side of his negro quarter, the inmates of which became sick. The first cases were of typhoid, and pleuro-pneumonia, and after the weather became warm, it assumed the type and character of typhoid fever. The members of his family both black and white, remote from the quarter, although not more than two hundred yards distant, but in an Easterly direction from the contaminated spot, were exempt from the disease. I feel certain that this disease had its origin as stated, and was strictly local, as the entire neighborhood was healthy. There were as many as 60 cases, and all were benefitted by quinine."

These, and other instances, which we have not space to detail, are sufficient to induce the belief that the decomposition of cotton seed by pro. cess of fermentation, produces a gas-probably the ammoniacal-which affects a majority of those who may be subjected to its deleterious agency. These effects of course will vary with the change of season, and in that revolution the constitution of the atmosphere induces varied types.

We have repeated instances presented to notice, where low, dirty buildings become the place of deposit for filth acted on by moisture, or the decaying of the logs, with which a large portion of our country houses are constructed, becoming the medium of disease.

Typhoid fever, as usually presented in this section of country, is variable in its character, in many cases attended with grave and malignant symptoms, owing in a great measure to locality; as for instance, in our prairies and low bottom lands; whilst on the other hand, there is more vascular excitement and inflammatory action in the hilly region of country.

In the former instance, Dr. Hogan, in his letter, says, "The disease is usually ushered in by a chill, not unfrequently a double tertian; the fever being remittent, with partial perspiration, great enteric irritation, terminating in special congestion, with a species of paralysis agitans, or, meningitis may supervene. There is more or less pulmonary congestion that is preceded by cerebral disturbance, sometimes in the form of delirium, and at other times it may be attended with stupor, or coma. In brief, typhoid fever may invade by the brain, the lungs, or the bowels, and in the grave cases, all these organs are apt to be involved, and your patient may die from exhaustion, in a physiological condition.

Whenever a patient is found with a dry red tongue, excessive tenderness of the abdomen, small fluttering, or wiry pulse, that is easy to be compressed, the eye dull, leaden and watery, morbid condition of the cerebral organs, and the bowels easily excited to action, we should not hesitate under ordinary circumstances, to pronounce it a case of typhoid fever of the low country.

Typhoid fever prevails in autumn, winter and spring; most usually the latter, and is met with annually in various sections of our country,

either sporadic, or prevailing as an epidemic on some particular plantation, attributable to local causes. The symptoms that mark this disease in the upland region are so very dissimilar in many respects from that of the low country, that we do not hesitate to adopt the true pathological signs, as furnished us by Dr. Clarke, a resident of Benton Co., Alabama, who says:

"The fever, typhoid,-was not ushered in by any distinct chill, but was some days in forming, and crept slowly on the patient. They grew dull, complained of being unwell, "and weak," the skin became dry and harsh, there was anorexia, headache, stupidity, and sleeplessness; there was at first some degree of constipation, subsequently diarrhoea; finally, more or less fever was developed, the pulse becoming accelerated, but always compressible, in some cases from 75 to 90, in others from 100 to 120. The skin usually became hot, especially about the head and across the abdomen; in some there was a tendency to coldness of the feet, which was difficult to remove; in others the feet like the rest of the surface became hot. The tongue by degrees assumed a redness on the edge, and in some bad cases was dry and fissured, there was dryness of the mouth, and constant calls for water.

"One marked symptom usually prevailed in every case, viz: intense pulsation of the carotids, the alvine evacuations frequently change as to consistence and color; the abdomen becomes tympanitic, in some cases highly so, and after a few nights insomnolency and delirium.

"The fever generally lasted from 15 to 21 days, and it was from 5 to 6 weeks after the patient complained of being unwell, before restoration to health."

This disease, like the various forms of pneumonia, prevails most among the negroes, especially in Middle and South Alabama. On some plantations two thirds of the residents are attacked with some form of the disease, and in many instances from 15 to 33 per cent. of those attacked have died.

The anatomical character of this disease from the examinations made by Dr. Clarke and the writer, appears to consist of an enlargement and softening of the spleen, dark leaden appearance of a portion of the small intestines, with now and then thickened, dark, ash colored patches in the ilium, which are easily scraped down; very little redness noticed any where in the canal, but on the contrary, a pale darkened appearance. In two cases that died in the Marine Hospital, there was ulceration of the eliptical plates of the ilium, such as the writer had seen in the Massachusetts Hospital; the mesenteric glands were enlarged in

every case.

Taking into view the rapid decline of severe autumnal fevers, together with the lessening mortality attending them and the rapid increase of those diseases just pointed out, the winter and spring diseases may now be regarded as the most fearful maladies within the borders of the State. To the negro, whose organization is such as to endure the heat of summer with impunity, these diseases which come on the chilly blast and are nourished by cold and moisture, are peculiarly noxious and alarmingly fatal.

In this section of the Union, scarlatina does not seem to be attended with the same degree of malignancy, as in the older States, neither has

it been noticed to observe the same periodic and epidemic character as presented elsewhere. As a general rule it may be said to be sporadic in its nature, some few cases appearing in various sections of the country every year, but generally mild and easily controlled by remedies.— There are however some exceptions in different localities where the disease has assumed a malignant type, but its fatality has usually been confined to a limited space, and but few years have been noticed when this form prevailed.

It would appear that whenever the disease is presented during the spring or mid-summer, its character is usually mild; but if in the autumn or winter it assumes a more malignant type. The winter and spring of 1844, were marked with great fatality consequent on this disease in the middle counties of the State. During that period the disease was complicated in its nature, assuming at times so much the appearance of rubeola with catarrhal affection as to warrant the belief of a distinct disease existing, and then again the two diseases were so intimately blended as to defy the utmost scrutiny of pathology.

The exanthematous affections like those of the thoracic viscera, are rapidly increasing, and if we are to judge by the effects generally pro. duced by physical changes, the day is not far distant when they will be. come the prominent disorders of the State, and the affections of summer and autumn, gradually yield to an improved state of cultivation. (To be continued.)

II.-Review of Opinions Concerning the Cause of the Coagulation of the Blood. By JOHN HARRISON, M. D. Professor of Physiology and Pathology in the Medical College of Louisiana.

There is perhaps no phenomenon more calculated to excite the attention of the curious than the coagulation of the blood-the rapid change of form from the liquid to the solid state was enough in itself to attract curiosity, but the interest if the subject was greatly enhanced, when the theories advanced in explanation were found to be so various, so contradictory, and so unsatisfactory. It is my purpose in the present paper to review these theories, they will present some curious specimens of medical logic upon indeed a very perplexing subject.

With the exception of one theory (that of Prévost and Dumas, etc.,) it is now conceded by all that the coagulation of the blood is due to the consolidation of the fibrine held in solution in the serum both together, they constitute the liquor sanguinis. The question, then, is limited to the cause of this change in the fibrine. But before taking up this question, it becomes us to give the theory of Prévost and Dumas, and show the grounds of its refutation.

According to Milne Edwards* their theory is as follows: "the attraction," say they, "which keeps the red matter fixed around the white globules having ceased along with the motion of the fluid, these globules

* Cyclopedia of Anat. and Physiology, Art. Blood.

are left at liberty to obey the force which tends to make them combine and form a net-work in the meshes, or amid the plates of which the colouring matter is included along with a great quantity of particles which have escaped this spontaneous decomposition."

Müller has the merit of overthrowing this theory,* which was for some time very generally received. His remarks are theset-"Berzelius, observing that lymph contains fibrine in solution, conjectures that the blood must also contain it in that state, because, he says, the lymph is a fluid seperated from the blood. Berzelius therefore suggested that the clot was formed by the fibrin coagulating and enclosing the red particles. This idea of the fibrin being in a state of solution in the blood has been advanced several different times, I have been so fortunate as to discover a definative proof of Berzelius' conjecture. In some frogs' blood which had been received in a watch-glass, I observed that before the whole mass coagulated some colourless transparent clots formed, which I could draw to the edge of the glass with a needle and on pouring off the blood, one or two minutes after it had flowed from the animal, I perceived that there were points or small fragments of similar coagula remaining adherent to the bottom of the glass. To this experiment it might be objected, that in amputating the frog's thigh, which is the readiest mode of obtaining blood from this animal, some lymph had escaped with the blood and had given rise to these coagula, I therefore collected the blood for the future, directly from the great ischiadic artery, which runs among the muscles at the posterior part of the thigh; I laid bare this artery, which is easily found on account of its running close to the great ischiadic or crural nerve, as it is usually called, and collected the blood from the artery only and with such care as to be sure that I had pure blood; I obtained blood in the same way from the heart, which is done with more facility. In this blood, of the purity of which there could be no doubt, the same small transparent coagula were always formed, before the entire mass of blood coagulated; a drop of this pure blood was diluted with serum, and placed under the microscope, the globules then appeared widely separated but in the spaces between them I could discern the formation of a coagulum which connected these bodies together however, with the intervals between them and by placing a needle between any two globules and moving it about, I could set the whole mass in motion; as the red particles of the frog's blood appear very large, when viewed by a high magnifying power, this experiment admits of the greatest accuracy, and is perfectly convincing. There is, however, an

* So, at least, it is frequently said. I do not know the date of Müller's experiment, but in a work published by Sir Charles Scudamore, in 1826, we find the following experiment and remarks. "Exp. 38. The Blood, immediately after being received in the basin, was kept briskly stirred with a piece of stick, and this being continued for a quarter of an hour, a mass of fibrine became twisted round it. The coloured portion in the basin remained permanently fluid, and from subsequent digestion of it in water, no more fibrine could be obtained. Hence we see, in a simple and familiar manner, that the solidification of the fibrine is the essential cause of the coagulation of the crassamentum of the blood. This fact of the separation of the fibrine by stirring the blood, is mentioned by Mr. Hewson." Essay on the Blood.

Elements of Physiology, p. 110, English Edit.

other and much easier, and indeed still more unquestionable method of demonstrating the same fact, knowing that the red particles of frog's blood are four times the size of those bodies in the blood of mammalia, I conjectured that although the red particles of the latter animals pass through filter paper, those of the frog might not. I found this opinion correct; thus as generally happens, the most simple means was the last thought of. I am now able to show at lecture, by an easy experiment, that fibrin is held in solution in the blood, that it passes limpid through the filter and then coagulates. The experiment can be made quite on a small scale, with the blood of a single frog; a small glass funnel and a filter of common white filter paper, or not very thick printing paper, are all the apparatus required. The filter must be of course previously moistened, and it is better to add some water to the blood as soon as the latter is poured into the filter; what then passes through is a perfectly clear serous fluid diluted with water and merely tinged in the slightest degree with the red colouring matter, which, in frog's blood, is not rapidly dissolved, sometimes it is quite colourless. If in the place of water a very dilute syrup containing one part of sugar in two hundred or more parts of water is employed, the red envelopes of the red particles is not at all acted on, and the filtered fluid is perfectly colourless. No globules can be discovered in this fluid, by the aid of the microscope; in a few minutes a coagulum forms, which on account of its transparency would not be remarked, were it not drawn out of the fluid with a needle. This coagulum gradually contracts, becomes whitish and fibrous, and then has exactly the aspect of human lymph.' The fibrin of the blood is by this means obtained in a purer state than is possible by any other method. Of course all the fibrin of the blood is not obtained by this process; the greater part of it coagulates before it can pass through the filter. To find the paper best adapted for the filter, some trials must be made with dif ferent kinds; if the paper is too thin, some few red particles pass through it with the fluid, and will afterwards be seen here and there in the coaguJum; if the paper be of a proper thickness, the coagulum will not contain a single red particle. There is no distinct appearance of granules in the fibrin thus obtained; it is quite hemogeneous; when it has contracted and become white, it acquires a finely granulated aspect. This appearance which it presents when viewed with the compound microscope may however arise merely from unevenness of the surface. There is another mode of proving that fibrine exists dissolved in the blood of the frog, as well as of the mammalia; by adding to the blood of man, or any vertebrate animal, some drops of a very concentrated solution of carbonate of potash, coagulation is retarded so that the red particles have time to subside; in the space of half an hour a soft coagulum forms, of which the inner part containing the red particles is red, while the upper is white."

A change in the fibrine constitutes, therefore, the coagulation. Is this change a chemical one, that is, so far as the composition of fibrine differs in the soluble or insoluble state; or is it one merely of form? All the effects of re-agents on fresh blood and upon coagulated fibrine, as well as the analogy and close resemblance, physically and chemicaly, between fibrine and insoluble albumen, lead us to the latter opinion,

But what causes this change, be it one in composition, or one merely of form? It was natural and proper that enquirers should turn their