The minute organisms peculiar to this disease act as the immediate exciting cause in all cases. These germs find ready access to the throat and nasal cavity, the parts most readily affected by the disease, being taken in by the act of respiration. The particular germs which are thought to be characteristic of this disease are more or less common in the air, especially in proximity to decomposing matter. It is their enormous numbers and extraordinary activity which give to diphtheria its dangerous character. In Fig. 338 may be seen a representation of the microscopical appearance of the Bacterium Termo and the Micrococcus, the two varieties of germs thought to have most to do with the production of diphtheria.

Fig. 338. Parasitic Fungi of Diphtheria. A. Micrococcus; B. Bacteria Termo.

Fig. 338. Parasitic Fungi of Diphtheria. A. Micrococcus; B. Bacteria Termo.

Since the disease is probably caused by germs, and since these very germs are produced in great abundance in the body of a person suffering with the disease, and thrown off with the breath and other excretions, it is evident that it may be communicated from one person to another. Clinical experience has verified this fact innumerable times. Experiments upon animals have also shown that the disease is communicable by inoculation. The affection is very appropriately called by one author a "miasmatic, contagious disease." On no other hypothesis can observed facts be reconciled. The disease is now gen erally recognized as contagious, and is treated as such by all enlightened physicians. The certain knowledge of this fact is sufficiently useful to well repay all the labor and time which have been devoted to the investigation of this malady. The period of incubation is usually two to eight days.

We believe that diphtheria may very appropriately be included in the class of diseases latterly known as filth diseases, since the parasitic organisms by which it is probably caused are apparently identical with those which flourish in organic filth. There can be no doubt that in decomposing, putrefying organic matter the germs of this disease are produced. One great source of such poisonous matters may load the air of a whole village with the poisonous germs, and thus expose to its ravages a whole community at once.

Neglected cesspools, foul vaults, leaky sewers, damp, unventilated cellars, moldy walls, all these and every other source of organic decay are the favorite haunts of these destructive organisms; and the only wonder is that cases of profound poisoning by these parasitic pests are not more common than they are. It is a mystery that so many escape.

What are termed spontaneous cases of the disease, that is, those which originated without previous exposure to contagion from a person suffering from this affection, are not uncommon. These cases undoubtedly originate from the production of germs by the usual sources of disease germs, which have already been indicated with sufficient definiteness. There are some who maintain that the spontaneous origin of the disease is impossible; but so many cases have appeared in which no connection could be traced to a preceding case that it seems to us to be pretty clearly established that it is possible for the disease to arise otherwise than by contagion. A few months since, a lady from an Eastern State came under our care for treatment of the effects of diphtheria, a very severe attack of which she had suffered. Upon inquiring into the history of the case we found it impossible to trace the disease to any other cause than exposure to the germs and spores of lower vegetable organisms. The house in which she was stopping was exceedingly damp, the walls, and even the door and window-casings being stained with green and brown mold. In personal conversation with Dr. Snow, of Providence, Dr. E. L. Griffin, President of the State Board of Health of Wisconsin, Dr. Ezra M. Hunt of New Jersey, Dr. R.C. Eedzie, President of the State Board of Health of Michigan, and various other distinguished sanitarians, we have learned of a large number of isolated cases of diphtheria which can be explained in no way satisfactorily but by the supposition that the disease originated where it occurred.

It is an observed fact that these germs, as well as those of other sorts, are remarkably tenacious of life. It is almost impossible to destroy them, either by boiling or by freezing as they will endure both extremes for hours without losing their vitality. The germs will even retain their virulent properties for months. A house in which a family had suffered with diphtheria was vacated for several months and on being again occupied, communicated the disease to its new inmates.

Drinking water, milk, and even beer, have been proven to be the vehicles of typhoid poison in many instances. There is good reason to believe that diphtheria may be communicated in this manner also, the liquids named being contaminated by absorption of the emanations of prolific sources of germ poisons, or by direct contamination with the excretions of a diphtheritic patient.

The common custom most prevalent among the gentler sex of rather indiscriminate kissing, bestowing especially frequent favors of this sort upon small children, cannot but be deprecated, at least during the prevalence of a diphtheria epidemic. There are on record numerous instances of the communication of most loathsome diseases through the seemingly harmless medium of a kiss; and there is a special danger respecting this disease which is well worthy of consideration. When an epidemic of diphtheria is prevalent, there are numerous cases, especially among adults, which are so very trivial in their general symptoms that the individual considers the difficulty nothing more than a cold, when he is really suffering with diphtheria, having distinct patches in his throat, and is, unconsciously sowing broadcast the seeds of disease wherever he goes. Such a person calls to see a neighbor and as usual smothers the baby with kisses and perhaps also kisses the larger children. What is the result? Very likely a week has not passed before the little one has diphtheria in a very severe form and possibty dies. Thus an act intended as one of affection, becomes literally the embrace of death. This hint is worth thinking of. Life is too valuable to be sacrificed by a kiss.

A few other means of contagion which we do not remember having seen mentioned are perhaps worthy of attention in a practical treatise like this. The disease may unquestionably be spread very rapidly by the use of a common drinking-cup at school or elsewhere. One of the worst cases of diphtheria we ever saw was in a little child who had taken the disease from a workman employed on the premises, by sipping water from the man's drinking-cup. The man suffered but slightly; but the little boy narrowly escaped without serious injury after a very severe illness, with extensive production of the false membrane. Toys and even books may also become the medium for communicating the disease, as well as articles of clothing, and anything that may become infected by the breath or expectorations of the patient.