CHOLERA 683 and in India, not merely by those whose opportunities of observing and treating the disease have been numerous, but by others specially undertaking such inquiries at the suggestion of Governments or other public authorities. Although many conflicting views have been propounded on the above-named points, the result of these investigations has been the collection of an amount of information sufficient to form the basis of a rational theory of cholera, and which may be expected yet to lead to the discovery of means to counteract the spread of this pestilence. The following points respecting the nature and mode of propagation of cholera are generally admitted by the best authorities : 1. That cholera is a specific disease depending upon the action in the human system of a morbid material (whether of the nature of a parasitic germ or a poisonous miasm being still undetermined) which is originally generated in certain parts of India, particularly in the delta of the Ganges and the flat lands around Madras and Bombay ; 2. That this infective material is capable of spreading from its centre of origin indefinitely, and thus cholera has appeared in an epidemic form in almost all countries ; and further that the disease may become acclimatized (endemic) in some places ; 3. That when it spreads abroad the vehicle of its trans mission is the discharges from the bowels of persons already affected ; and that from these the cholera-infecting matter is exceedingly apt to be diffused through the air, to con taminate water, and to become attached to clothing, bed ding, furniture, &c., and in these various ways to find ready entrance through the lungs or alimentary canal into the bodies of healthy persons, where it is capable of developing the disease in a more or less severe form according to the quantity introduced ; 4. That cholera is thus in a certain sense contagious ; 5. That overcrowding and other insanitary conditions, particularly the presence of decomposing organic matter, afford the conditions favourable to the multiplication of the cholera matter, and thus tend to spread the disease, although of themselves incapable of originating it. But even admitting these propositions, it is obvious that they are insufficient to explain the intense tendency of cholera to spread widely at some times more than others. Without alluding to the various hypotheses which have been advanced on this point, it seems probable, from the history of the disease as exhibited both in Europe and in India, that various factors may alone or together be concerned in the rise and spread of epidemics of cholera. It is stated that a high temperature favours the development of cholera, and in general this appears to be the case, but it is by no means invariable, as some of the most severe epidemics raged with greatest fury in winter. That cholera might be carried by the agency of winds from one country to another must be held as a possibility, although no satisfactory evidence exists upon the point More probable are the theories which assign to local conditions an important part in the propagation of cholera. With regard to mere locality it appears that the disease has been generally found to prevail more extensively and with greater virulence in low-lying districts than in elevated situations. In connec tion with this, the relation of the character of the soil to the propagation of cholera has been elaborately investigated by Professor Pettenkofer of Munich, whose work in this department has attained world-wide reputation, and who ascribes a powerful influence in the diffusion of the disease to the ground-water of a locality where cholera is pre vailing, shallow, porous soils affording, according to his views, special facilities for the reception, proliferation, and distribution of the so-called cholera germs. Further, the observations of Dr Snow, Dr Frankland, and Mr Simon in certain epidemics of cholera in London have conclusively connected outbreaks of the disease in various districts with the use of drinking-water contaminated with the discharges from cholera patients. All investigations appear clearly to show that the prime factor, and that without which no other conditions can take effect, is the introduction into the local ity of the specific infecting matter, this being accomplished in general by the arrival of infected persons, for cholera epidemics, as is well known, spread mostly in the lines of human intercourse and travel. But further, in this as in other acute infectious diseases, a special liability of indi viduals must be admitted, as is proved by the fact that among persons living under precisely the same conditions some will suffer while others escape, and likewise that persons inhabiting cholera districts may come to enjoy an immunity from attacks of the disease. Among known pre disposing causes, the incautious employment of purgative medicines, the use of unripe fruit, bad and insufficient food, intemperance, personal uncleanliness, overcrowding, and all kinds of unfavourable hygienic surroundings play an im portant part during the course of any epidemic of cholera. In describing the symptoms of cholera it is customary to divide them into three stages, but it must be noted that these do not always present themselves in so distinct a form as to be capable of separate recognition. The first or pre monitory stage consists in the occurrence of diarrhoea. Fre quently of mild and painless character, and coming on after some error in diet, this symptom is apt to be disregarded. The discharges from the bowels are similar to those of ordin ary summer cholera, which the attack closely resembles. There is, however, at first the absence of vomiting. This diarrhoea generally lasts for two or three days, and then if it does not gradually subside either may pass into the more severe phenomena characteristic of the second stage of cholera, or on the other hand may itself prove fatal. The second stage of cholera is termed the stage of col lapse or the algide or asphyxial stage. As above mentioned, this is often preceded by ths premonitory diarrhoea, but not unfrequently the phenomena attendant upon this stage are the first to manifest themselves. They come on often suddenly in the night with diarrhoea of the most violent character, the matters discharged being of whey-like appear ance, and commonly termed the " rice-water " evacuations. They contain large quantities of disintegrated epithelium from the mucous membrane of the intestines. The dis charge, which is at first unattended with pain, is soon succeeded by copious vomiting of matters similar to those passed from the bowels, accompanied with severe pain at the pit of the stomach, and with intense thirst. The symp toms now advance with rapidity. Cramps of the legs, feet, and muscles of the abdomen come on and occasion great agony, while the signs of collapse make their appear ance. The surface of the body becomes cold and assumes a blue or purple hue, the skin is dry, sodden, and wrinkled, indicating the intense draining away of the fluids of the body, the features are pinched and the eyes deeply sunken, the pulse at the wrist is imperceptible, and the voice is reduced to a hoarse whisper (the vox cholerica). There is complete suppression of the urine. In this condition death often takes place in less than one- day, but in epidemics cases are frequently observed where the collapse is so sudden and complete as to prove fatal in one or two hours even without any great amount of pre vious purging or vomiting. In most instances the mental faculties are comparatively unaffected, although in the later stages there is in general more or less apathy. Reaction, however, may take place, and this constitutes the third stage of cholera. It consists in the arrest of the alarming symptoms characterizing the second stage, and
the gradual but evident improvement in the patient s con-
