Page:EB1911 - Volume 20.djvu/830

Rh combination with other organisms. It has been observed that cancerous and other mahgnant tumours appear to recede under an attack of erysipelas, and certain cases have been recorded by both Fehleisen and Coley in which complete cessation of growth and degeneration of the tumour have followed such an attack. As the streptococcus of erysipelas can be isolated and grown in pure culture in broth, it was thought by these observers that a subcutaneous injection of such a cultivation might be of value in the treatment of cancerous tumours. No difficulty was experienced in setting up erysipelas by inoculation, but in some cases the process was so acute that the remedy was more fatal than the disease. The virulence of the streptococcus of erysipelas, as pointed out by Fehleisen and Coley, is greatly exalted when the coccus is grown alongside the Bacillus prodigious and certain other saprophytic organisms which flourish at the body temperature. It is an easier matter to control the action of a non-multiplying poison, even though exceedingly active, than of one capable, under favourable conditions, of producing an indefinite amount of even a weaker poison. The erysipelatous virus having been raised to as high a degree of activity as possible by cultivating it along with the Bacillus prodigious — the bacillus of " bleeding " bread — in broth, is kQled by heat, and the resulting fluid, which contains a quantity of the toxic substances that set up the characteristic erysipelatous changes, is utilized for the production of an inflammatory process — which can now be accurately controlled, and which is said to be very beneficial in the treatment of certain malignant tumours. The accurate determination of the aetiology of erysipelas has led to the adoption of a scientific method of treatment of the disease. The Streptococcus erysipdatis is found, not speciaUy in the zone in which inflammation has become evident, but in the tissues outside this zone: in fact, the streptococci appear to be most numerous in the lymphatics of the tissues in which there is little change. Before the appearance of any redness there is a dilatation of the lymph spaces with fluid, and the tissues become slightly oedematous. As soon, however, as the distension of vessels and the emigration of leukocytes, with the accompanying swelling and redness, become marked, the streptococci disappear or are imperfectly stained — they are undergoing degenerative changes — the inflammatory " reaction " apparently being sufficient to bring about this result.

If it were possible to set up the same reaction outside the advancing streptococci might not a barrier be raised against their advance? This theory was tested on animals, and it was found that the application of iodine, oil of mustard, cantharides and similar rubefacients would prevent the advance of certain micro-organisms. This treatment was applied to erysipelatous patients with the most satisfactory result, the spread of the disease being prevented whenever the zone of inflammation was extended over a sufficiently wide area. The mere " ringing " of the red patch by nitrate of silver or some other similar irritant, as at one time recommended, is not sufficient: it is necessary that the reaction should extend for some little distance beyond the zone to which the streptococci have already advanced.

Gonorrhoea. — A micro-organism, the gonococcus, is the cause of gonorrhoea. It is found in the pus of the urethra and in the conjunctiva lying between the epitheUal cells, where it sets up considerable irritation and exudation; it occurs in the fluid of joints of patients affected mth gonorrhoeal arthritis; also in the pleuritic effusion and in the vegetation's of gonorrhoeal endocarditis. It is a small diplococcus, the elements of which are flattened or shghtly concave disks apposed to one another; these, dividing transversely, sometimes form tetrads. They are found in large numbers, usually in the leukocytes, adherent to the epithelial ceUs or lying free. They stain readOy with the basic aniline dyes, but lose this stain when treated by Gram's method. The gonococcus is best grown on human blood-serum mixed with agar (Wertheim), though it grows on ordinary solidified blood-serum or on blood-agar. Like the pneumococcus, it soon dies out, usually before the eighth or ninth day, unless reinociflations are made. It forms a semi-transparent disk-Uke growth, with somewhat irregular margins, or with small processes running out beyond the main colony. It acts by means of toxins, which have been found to set up irritative

changes when injected, without the gonococci, into the anterior chamber of the eye of the rabbit, j^ usau tii^am.

2. Caused by Specific Bacilli. • ■."•..»

(a) Acute Infective Fevers. ■ • -v.^^t rr

Cholera. — In 1884 Koch, in the report of the German Cholera Commission in Egypt and India, brought forward overwhelming evidence in proof of his contention that a special bacterium is the causal agent of cholera; subsequent observers in all countries in which cholera has been met with have confirmed Koch's observation. The organism described is the " comma " bacillus or vibrio, one of the spirUla, which usuaUy occurs as a shghtly curved rod i to 2n in length and 0-5 to Q-6fi in thickness. These comma-shaped rods occur singly or in pairs; they may be joined together to form circles, half-circles, or " S "-shaped curves (see Plate II. fig. 3).

In cultivations in specially prepared media they may be so grouped as to form long wavy or spiral threads, each of which may be made up of ten, twenty, or even thirty, of the short curved vibrios; in the stools of cholera patients, especially during the earlier stages of the disease, they are found in considerable numbers; they may also be found in the contents of the lower bowel and in the substance of the mucous membrane of the lower part of the small intestine, especially in the crypts and in and around the epithelium lining the follicles. It is sometimes difficult, in the later stages of the disease, to obtain these organisms in sufficiently large numbers to be able to distinguish them by direct microscopic examination, but by using the Dunbar-Schottelius method they can be detected even when present in small numbers. A quantity of faintly alkaline meat broth, with 2 % of peptone and I °o common salt, is inoculated with some of the contents of the intestine, and is placed in an incubator at a temperature of 35° C. for about twelve hours, when, if any cholera bacilli are present, a delicate pellicle, consisting almost entirely of short " comma " bacilli, appears on the surface. If the growth be allowed to continue, the bacilli increase in length, but after a time the pellicle is gradually lost, the cholera organisms being overgrown, as it were, by the other organisms. In order to obtain a pure culture of the cholera bacillus, remove a small fragment of the young film, shake it up thoroughly in a little broth, and then make gelatine-plate cultivations, when most characteristic colonies appear as small greyish or white points. Each of these, when examined under a low-power lens, has a yellow tinge; the margins are wavy or crenated; the surface is granular and has a peculiar ground-glass appearance; around the growing colony liquefaction takes place, and the colony gradually sinks to the bottom of the liquefying area, which now appears as a clear ring. The organism grows very luxuriantly in milk, in which, however, it gives rise to no very noticeable alteration; its presence can only be recognized by a faint aromatic and sweetish smell, which can scarcely be distinguished from the aromatic smell of the milk itself, except by the most practised nose.

The cholera bacillus may remain alive in water for some time, but it appears to be less resistant than many of the putrefactive and saprophytic organisms. It grows better in a saUne solution (brackish water) than in perfectly fresh water; it flourishes in serum and other albuminous fluids, especially when peptones are present. Its power of forming poisonous substances appears to vary directly with the amount and nature of the albumen present in the nutrient medium; and though it grows most readily in the presence of peptone, it appears to form the most virtilent poison when grown in some form or other of crude albumen to which there is not too free access of oxygen. From the experiments carried out by Koch, Nicati and Rietsch, and Madeod, there appears to be no doubt that the healthy stomach and intestine are not favourable breeding-grounds for the cholera bacillus. In the first place, it requires an alkaUne medium for its full and active development, and the acid found in a healthy stomach seems to exert an exceedingly deleterious influence upon it. Secondly, it appears to be incapable of developing except when left at rest, so that the active peristaltic movement of the intestine interferes with its development. Moreover, it forms its poison most easily in the presence of crude albumen. It is interesting to note what an important bearing these facts have on the personal and general spread of cholera. Large quantities of the cholera baciUus may be injected into the stomach of a guinea-pig without any intoxicative or other symptoms of cholera making their appearance. Further, healthy individuals have swallowed, without any iU effect, pills