and for some heart affections, but in England we are rather shy of using this possibly two-edged tool for such complaints.

In conclusion, I should say that the methods I myself most often use and find most useful are solid CO2, heat from these incandescent lamps, X-rays in superficial skin and malignant diseases, after operations for breast and other cancers, for ringworm of the scalp and for sciatica, ionization for sciatica, lumbago, etc., high-frequency for piles and fissures.

ROUTINE OF PRACTICAL VACCINE THERAPY

BY DR. HORACE GREELEY,
Brooklyn, New York

THE natural processes by which all solid and insoluble materials, such as dead body-cells, occurring within the system, are rendered soluble and eliminated depend upon digestive activities akin to those which, within our alimentary canal, reduce our food to the assimilable state. While these latter are mainly dependent upon special enzymes, secreted by particular glands, modern research indicates that the leucocytes take a prominent part, since their number is so massively increased in the gastro-intestinal villi during active digestion, as well as in the general circulation shortly after a meal. However, parenterally-without the digestive tract, but within the body-the leucocytes are the dominating digestive elements, and, while all body-cells, in common with all cellular life, have digestive activities, these are exercised mainly for their metabolic processes of self-nutrition and normal function. Even if every cell of the various body tissues contributed to the general waste-rendering work, the inability of all, with two exceptions, to either move about (red bloodcells are more properly special cellular products than actual cells) or to actively multiply would greatly restrict their power to meet unusual requirements, as would be presented by a mass of dead adjoining cells or of invading parasites. These two exceptions are the leucocytes aforementioned and the connective tissue cells whose proliferation responds so quickly to local irritation. These latter cells, however, are probably effective to only a very minor degree, and all belief in special activity on their part is based upon their ability to multiply under the stress of inflammation, and the phagocytic possibilities of some of their variations, as the multinuclear cells of tubercles.

Of course, since every body-cell contributes its excretory quota to the general plasma, and since it is certainly probable that each and every one forms a proteolytic enzyme, it cannot be denied that, as a whole, the body-cells may, especially under unusual stimulation, add

to the active enzymes of the plasma; yet all the phenomena of tissue resolution and inflammation show that in this particular the major rôle is always played by the lymphatic cells, and that wherever these be lacking liquefaction processes are always most protracted and infections prone to spread or to become chronic.

Therefore, when infectious agents have penetrated the tissues, the only power competent to remove them or the solid residue of their activities is this proteolytic function, which, for the reasons just given, as well as the well-known phenomena of phagocytosis and the enzymic activity in vitro of leucocyte extract, depends principally upon the leucocytes. Of course, soluble products of parasitic activity, such as the toxins-formed in appreciably active quantities by the diphtheria and the tetanus bacillus are not included, since they would be easily eliminated by the usual avenues were it not for the great affinity which particular body-cells have for them—an affinity which, of course, is reflected in the antitoxins that, it is surmised, are but an extension of the special cell sensitiveness to the bloodwhether through the addition thereto of derivatives from the susceptible cells, or otherwise, has not been determined. Toxin-antitoxin combination seems to fall in with the general body-waste in process of excretion.

It may be stated as a general rule that any non-specifically immunized animal is susceptible to any microorganism that can gain access to its tissues and survive under the physical and nutritional conditions existing. Now the very fact that an invading organism can make use of the normal body materials necessitates the possession by it of enzymes akin to those of at least some of the body's cells which feed on the same pabulum, and since these enzymes affect the wear and tear of the parasite's economy, as well as its upbuild, the related body-cell enzymes must possess at least some such action upon the parasite. Every living body-cell evidently has the ability to ferment, digest, its protein food, and while in the case of the fixed cells, feeding on the plasma only, this food being especially prepared and of stable composition, the enzymes required are probably of the simplest, those elaborated by the leucocytes-the wandering scavenger cells must be of such a character and power as to affect each and every other protein structure of the body in order that they may efficaciously remove waste from every organ; further, every body

cell contributes its quota to the plasma, and, therefore, any enzymic action possessed by it (the plasma) must be a complex of the whole.

With the foregoing considerations in mind, we can understand that, when a parasite first begins development within the host, the latter's plasma enzymes react, at least slightly, with its peculiar proteins, either as presented by the surface of the individual organisms, or by material discharge therefrom. So soon as this takes place, the well-known effect of increased use of a body product in stimulating increased production comes into play, and soon the plasma enzymes, through such stimulation, become sufficiently powerful to effect appreciable proteolysis of at least the surface material of some of the parasites, resulting in a layer of protein decomposition products, albumose or peptone, perhaps, of the same chemical nature as body waste products which the leucocytes are accustomed to engulf, phagocytose, and reduce in their ordinary routine. After this coating or partial digestion (sensitization), and only then, the parasites are actively attacked by the leucocytes. Of course, the living parasites or the partial decomposition products of parasites may, when a given leucocyte is exposed thereto under unfavorable conditions, such as too great concentration either of germs or products, destroy that cell.

When the products of the action of the moderately strong plasma enzymes upon the parasites, or those of any incomplete phagocyte digestion, when the cell has perished before completing it—albumose, peptone, or like substances-pass into solution in the plasma in amounts which are physiologically active, we get the first symptoms of infectious disease. These symptoms are due to the poisonous action of the said incompletely digested parasites, and are the same as would be produced by the peptone of ordinary gastric digestion.

Digestion of parasites by phagocytosis, since the leucocytes, as explained, are complete protein digestion machines, being producers of the most powerful and most generally applicable proteolytic enzyme, may be regarded as being usually so complete-unless the phagocyte dies during the process-as to reduce the decomposition products, before they escape from the phagocyte, beyond the point at which they could act as irritants, just as continued proteolysis, in enteric digestion, carries peptone, a cellular poison, into amino-acids, which are entirely innocuous under all conditions. However, as the disease progresses, even the plasma enzymes may become powerful

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enough to effect a complete disintegration (to amino-acid stage) of the infecting agents presenting, when one would expect symptoms to often subside by crisis, which they do, since the partially digested products, which alone irritate the tissues, could no longer accumulate in nor be disseminated by the plasma.

A word or two should be said about leucocytosis. In the first place, it is plain that the withdrawal of the products of an organ or a tissue, as in the simple example of the milk or any gland secretion, directly stimulates the formation of new products. This acts through a reduction in the pressure exerted on the producing cells, and their consequent swelling, which sucks in a new plasma supply from the increased blood influx influenced by the same diminution of pressure, the whole resulting in greater nutrition, growth, function, and reproduction-if cells possess this power. Now, since the main sources of the leucocytes are the lymphatic tissues, bone-marrow, lymph glands, etc., if anything causes a withdrawal of leucocytes therefrom, the formation of new leucocytes will be stimulated, and, as when stimulated these cells exhibit marked amoeboid movements, such stimulation would alone increase the rate of exit from a gland, for example, of its leucocyte inmates. Therefore, if we have an infection whose agents, or their products, circulating in the lymph, reach and stimulate the leucocytes of the bone-marrow, lymph glands, and other such tissues generally, we are certain to have both an increased presence of these cells in the peripheral circulation, and an increased production thereof in the lymphatic tissues, for the reasons given. We now have to decide what constitutes a stimulus to a leucocyte, and since, in connection with the relation of these cells to parasites, we need not consider physical changes in surroundings, we are limited to the irritant or chemical action which may be exerted. A leucocyte, besides being an embryonal cell type, exhibits metabolic activities representative of those of all other body-cells, and, as a consequence, it is, to at least some degree, susceptible to each and every influence that an infecting agent can exert upon any other body-cell. Therefore, just so soon as parasitic products reach a leucocyte its activity is directly stimulated. Of course, the extent of the stimulation varies according to the nature and amount of the stimulating agent and, perhaps, even according to the vigor of the individual's lymph tissue, so we accordingly find infections such as