been so disconnected, that to the ordinary student the relationship is lost, and few we fear could claim to understand what is definitely known and has been proven concerning it. Prof. Hugo Engel, of Philadelphia, has lately delivered a lecture on the subject, the full report of which was published in the Medical and Surgical Reporter of October 11, 1884, and constitutes a most valuable contribution to the literature of the day. That our readers may have the benefit of its salient points, we present here a resumé of it.

"At the boundary between the vegetable and animal kingdom there is an immense empire of minute beings, too small to be visible to the naked eye. So difficult becomes here the distinction between animal and plant, that for a long time even experts were in doubt to which of the two kingdoms these micro-organisms belonged. The question seems not yet definitely settled, though the majority of the observers incline to the belief that they must be classed to the vegetable kingdom. There are two great subdivisions of these minute beings Hyphomyceti and Schizomyceti. The first, so-called moulds or fungi, multiply mainly by the aid of spores. They are parasites, many of which give rise in the human being to diseases of the skin and mucous membrane, as favus, aphthæ, etc. The propagation on the other hand of the schizomyceti takes place mainly by division, and it is with the last we have here to do.

Most of the schizomyceti having a rod-like shape, they have received the generic term of bacteria. But not all bacteria are so formed, and according to their morphological peculiarities they are subdivided as follows:

1.

Micrococci or Cocci, characterized by their circular shape. 2. Bacilli, by which term are understood all rod-shaped bacteria, whether short or long.

3. Bacteria proper, as which science recognizes only the very shortest bacilli.

4. Vibriones, also rods, but of wavy shape.

5. Spirilli, forming short stiff screws; and,

6. Spirochaeti, which appear as long flexible screws.” These bacteria under favorable conditions for their development have great productive power, and if no impediments were placed in their way would overpower every living organism for it has been shown that one in three days became 47 trillions. They can however propagate only under certain conditions. "For instance, their most common kind, the septic bacteria, cannot obtain sustenance from the healthy living human or animal body; and what difficulties they have here to overcome, may be judged from the fact that in the blood and tissues of healthy beings not a single bacterium has ever been found,

But the enormous propagation of septic bacteria at once begins where death has interrupted the mechanism of life, and the organized tissue having ceased its motion, is decomposed, decays, ferments, and putrefies. And it is to-day a recognized fact, undisputed by any authority, that the process of putrefaction, by which the dead organized substance loses the form and the composition of its constituent parts, is not only accompanied by the development of bacteria, but is in fact caused by it and kept up by it alone. But not decay and putrefaction alone are caused by these microbes; there are many chemical processes, known by the name of fermentations, which have been proven to depend upon the vital process of bacteria, or other micro-organisms related to them.'

The researches of modern times have added to these known phenomena the proof of the supposition of Henle that a contagium vivum was the pathogenic cause of infectious diseases. "The first discovery of this kind Pollender and Brauell made, independently of each other, by detecting peculiar small rods in the blood of animals and human beings suffering from anthrax. Thanks to the labors of Davaine, Bollinger, Klebs, Pasteur, and especially Koch, it is now generally recognized that these small rods are genuine bacteria, species bacilli, and that they are really the pathogenic cause of of anthrax. Investigators next succeeded in demonstrating the constant presence of certain bacteria in all morbid processes belonging to the great group of septico-pyæmic diseases. The definite proof of their character as pathogenic elements has thus far been given by Klebs of the micrococci causing septic cystopyelonephritis; by Rindfleisch, Klebs, and others, of the micrococci producing septicæmia and pyæmia; by Luke and Kocher of the cocci inducing osteomyelitis, and those of erysipelas by Nepven, Orth, Billroth, Klebs, etc. Also in septic ulcerative endocarditis, whose cause was so long an enigma to physicians, the constant presence of micrococci-colonies can be easily demonstrated. The micro-organisms of diphtheria have not yet been discovered; neither have those of variola, scarlatina, morbilli, acute yellow atrophy, and hæmophilia neonatorum been detected. But the micrococci causing gonorrhea, discovered by Meisser, and those of croupous pneumonia, detected most recently by Friedlander, are now recognized as elements constantly present in these diseases.

The discovery of Obermeyer, that in the blood of persons suffering from relapsing fever during the febrile stage innumerable screw-bacteria were invariably found, produced a deep impression upon investigators, and soon from all sides proofs were adduced. As further acquisitions, definitely proven, may be considered the discovery of lepra-bacilli by Hausen and Weisser; of the typhoid

bacilli by Klebs, Eberth, Koch; of the tubercle bacilli by Koch and Baumgarten; of the bacilli of glanders by Schutz and Israel. They can easily be demonstrated in recent cases, if the methods of investigation described by their discoverers be employed; and their constant occurrence in the diseases mentioned is generally acknowledged. The bacteria described as syphilis-bacilli, by Klebs and others, and the malaria-bacilli, detected by Marchiafava, Klebs, and Tommasi, have not been confirmed by the other observers. While enumerating these discoveries, I will ultimately mention that of Koch, who found in the intestines and the dejections of cholera patients the so called comma-bacillus never absent.

We may say, therefore, that in a large number of general and local infectious diseases, peculiar schizomyceti, with special characteristics in every malady, have been proven to be constantly present. The view once held that, what had been taken for bacteria, were really products of the granular decomposition of tissues, may be said to have long since exploded. The recent improvements in bacterioscopic technic, and the discovery of the pure-culture of these microbes by Klebs, Pasteur, Koch, Ehrlich, and others, have enabled investigators to give undoubted scientific proof of the existence and recognition of the bacteria. There, further, is to-day no longer the slightest suspicion of their being a post-mortem product.

To enumerate all the various species of micrococci which have been proven pathogenic elements, would lead me too far. I will only state the fact that scientists agree that the proof has been given of erysipelas, that it is caused by micrococci.

There are amongst the schizomyceti varieties which do not give rise to infectious diseases. To these positively non-pathogenic bacteria belong the bacterium termo, the cause of putrefaction, many micrococci, as the common pigment-cocci, then the so-called hay-bacilli, many other bacilli, producing fermentation, and most real vibriones, spirilli, and spirochaeti.

Then there are bacteria, not strictly pathogenic, but dangerous to the human race, as they put up their abode in parts of the organism which have lost most of their vitality, or have become mortified, and in which these microbes cause putrid decomposition, whose products, if absorbed and carried into the blood, act as poisons upon the system. To these belong all septic bacteria; they develop only under the condition named, and in the healthy living being they cannot propagate.

Some varieties again, as the bacilli of lepra, relapsing fever, typhoid fever, cholera, etc., multiply only in the human organism, while others grow and develop in the animal body alone, and again other do so in both.

Still it may surprise, when considering the power of multiplication of these bacteria, their presence in enormous quantities in diseased tissues, and the fact that morbid material alive with them, and products of tissue-change from the infected organism reach in various ways the outer world, and there are spread through the air, in water, food, etc.-it may surprise, I say, that under these circumstances in the course of a long life not every human being becomes the victim of all the various pathogenic bacteria, and affected with all the infectious diseases. Let us consider this question.

A large part of the pathogenic schizomyceti are not capable of development and multiplication except under conditions, such as they exist only in the interior of the living human (animal) organism.

These bacteria, called endogenous microbes, cannot preserve, therefore, in the world outside the living body, their virulent properties, or but for a short time; their multiplication, upon which their pathogenic character depends in the outer world, under natural conditions, is, therefore, an utter impossibility. In general, infection with such endogenous schizomyceti is therefore, possible only when you are brought into direct contact with the diseased body, or its recently discharged products, or if you approach very near to them; and the danger of infection by contact or by near approach will greatly depend upon the fact whether the pathogenic bacteria can pass through the air in sufficient quantities, and in a fertile condition, over into another living human body, or whether for this end a more or less continuous contact of fluid or solid morbid material, containing the living bacteria with the injured skin or mucous membrane, is a necessity.

The danger of infection would appear to be greater in ektogenous pathogenic micro organisms, i. e., those which can develop and multiply also outside the living being. But experiments have shown that an infection by simple inhalation, as formerly supposed, is by no means frequent in these cases, and with some varieties, as for instance, anthrax, it never takes place. The anthrax bacilli, if they do not develop directly in an open sore or wound, must be swallowed, and cannot infect the human being simply by being inhaled. The bacteria of pyæmia and septicæmia, the comma-bacilli of cholera and others, can neither become dangerous to the human organism if inhaled; while the cocci of pneumonia seem to be the only ek togenous schizomyceti which threaten the human being in this manner alone.

It is an undoubted fact that we may easier escape from a danger coming to us in the shape of the water we drink, or the food we eat, or threatening us by contact, than we could guard against the inhalation of bacteria. The first we may prevent, the last we cannot. Then

nature herself has taken care that these microzymes shall not overwhelm the human race. As I said before, so many conditions must favor the development of the most virulent micro-organisms, that the observations thus far made promise, that the day will not be distant, when we shall succeed in driving the whole breed from the neighborhood of civilized humanity."

L. A. F.

ESCHAROTICS.

In a late article emenating from the Biological Labratory of the University of Pennsylvania (Med. News. Jan. 24th), by Drs. Randolph and Gibson, attention is called to the painless character of an escharotic composed of a saturated solution of the hydrochlorate of cocaine in strong nitric acid. The success of such a method suggests the value that might accrue in certain dental manipulations with escharotics, used in connection with this drug. Here is an idea, will some one work it out and let us hear the result?

In the short article on Perforated Teeth which appeared in the Dental Practitioner for January, the statement is made that, in the text books nothing is found treating of the subject in question. This statement was made after considerable search and some inquiry and deemed correct. Since then the writer's attention has been called to the fact that in Dr. Flagg's "Plastics and Plastic Filling" the subject is treated in substantially the same manner as in the article mentioned. Strangely enough this was overlooked, although the book was examined before the article was written, but in this examination the unobtrusive paragraph escaped his notice.

It may seem strange that familiarity with the book named did not prevent the apparent plagiarism, but it is two or three years since the volume was read, a daily intercourse with Dr. Flagg having made its methods practically familiar, and taken the place of re-perusals.

In describing the operation of treating a perforated tooth the writer simply stated his usual methods of procedure, utterly unconscions that he repeated, almost word for word, the description given on, p. 138 of "Plastics and Plastic Filling." This similarity doubtless arises from the fact that his practice is identical with that of Dr. Flagg, being based on the teachings of the latter. A. B. HARROWER.

Phila. Jan'y. 20, 1885.