poisonous to nearly all other microbes. Dr. Bergeon and others have used this gas in consumption by injecting it per rectum. Claude Bernard has shown that gases which are poisonous when breathed may be introduced into the blood in some other way without poisoning. Bauman, a pupil of Liebig, claims to have cured. consumption in the early stages by having the patients breathe in rooms in which sulphur was burning. For the first ten days the cough and irritation increased; afterwards the patients rapidly improved.

Free oxygen is germicidal to some microbes. Ozone is found especially in the high regions of the atmosphere and in sea air. Microbes are least numerous in these regions. Ozone destroys microbes, and it is supposed that it does so by decomposing organic matter and setting free the oxygen. The advantages of residence of consumptives in high altitudes, as the Swiss mountains, is partly explained in this way. Oxygenated water acts like ozone.

Air saturated with oil of turpentine is germicidal. There is a popular and seemingly well-grounded belief that the air of a country well wooded with turpentine trees is useful in preventing and curing consumption. Skoda says that moist air with turpentine vapor is useful in gangrene of the lungs.

The salts of quinine destroy both pathogenic and non-pathogenic microbes. They destroy the bacillus malaria. The best salt for therapeutic purposes is probably the hydrochlorate. The dose by mouth must be proportioned to the severity of the case or intensity of the poison. Stanley, in Darkest Africa, took doses of 45 to 50 grains.

The alcohols are antiseptic and germicidal; will arrest the development of microbes and spores; but the spores, once formed, are said to resist strong alcohol for months. The destruction and prevention of putrefactive germs is well shown in the use of alcohol in laboratories of anatomy, pathology, etc.

There are many other lesser germicides which I need not stop to mention. The tendency of the present day is to rely less on disinfectants and more on absolute cleanliness. If we should visit one of our best hospitals we would see the ceilings and walls painted, because it has been found that wall-papers accumulate germs and dust; the paint can be readily cleaned. There are no carpets on the floors nor woolen curtains at the windows, because of the same objection; the floors are painted, varnished, or oiled;

the windows are shaded by shutters or light curtains. Water pipes, closets, and bath tubs are exposed, so that dirt cannot accumulate nor leakage occur without being at once noticed. Gas is replaced by electricity to avoid contamination of the air by the products of combustion. Hot air from a furnace is replaced by hot-water heating, or the air is screened as it enters the building. The water used for drinking and the preparation of food is boiled to free it from possible organic substances that might be hurtful. Every other possible precaution is taken to prevent the introduction of poisonous microbes. The instruments used in operations are made entirely of metal, and can be placed, box and all, in boiling water before using, to destroy all possible germs. The operator keeps himself clean; wears overgarments of linen or some non-woolen material. The subject for operation is handled only so much as is necessary; only a limited number of assistants and spectators may be present. The effect of all this precaution has been to diminish largely the mortality; serious consequences which formerly were not unexpected would now be an opprobrium to the operator and the hospital. Speaking generally, such a place is far better for treatment of sick and injured than any private house, even that of the most wealthy.

The diseases which are known or believed to be caused by microbes, or their products, are about 40 in number. Among them are cerebro-spinal meningitis, chicken cholera, Asiatic cholera, so recently at our doors; dental caries, which is the staff of life to thousands of dentists; diphtheria, erysipelas, glanders, hydrophobia, leprosy, malaria, measles, pleuro-pneumonia, puerperal fever, pyæmia, scarlet fever, swine fever, tetanus, commonly known as lock-jaw from one of its prominent symptoms; tuberculosis, typhoid fever, small-pox, vaccine disease, and yellow fever. These diseases are most dreaded; they decimate populations, and yet are most easily prevented.

In hydrophobia or rabies there is a micrococcus, which, however, has not yet been isolated and cultivated, found in the nervous system.

In yellow fever micrococci are found in the kidneys, spleen, and liver. The disease is worse during the heated term and ceases with frost.

In erysipelas they are found in the lymphatic vessels of the skin. In small-pox, also in the lymphatics of the skin.

In pneumonia, in the sputa and blood. The disease can be produced in some of the lower animals by spraying the microbes in the animals' cages.

In whooping-cough an oval-shaped micrococcus is found, but has not yet been isolated.

In measles, micrococci are found in the skin, blood, and catarrhal exudations.

In scarlet fever, in the blood, exudations, ulcerated throat, scaling of skin, and in urine; found also in the milk of cows suffering with certain diseases of the udder.

In gangrene there are small oval micrococci.

In cattle plague, micrococci are found in blood and lymphatic glands.

In cerebro-spinal meningitis, in the pus at base of brain and in kidneys.

In puerperal fever, found in endocardium, lung, spleen, kidney, brain, etc. An alkaloid has also been found in the organs of those dead of the disease and in the urine of patients. To prevent the fever, an antiseptic treatment of the lying-in patient should be adopted.

In what is called suppuration the microbe micrococcus pyogenes aureus is found.

In septicemia, micrococci and bacteria are found in great numbers.

In chicken cholera the bacteria cholera gallinarum is found in large numbers in the blood and organs of fowls dead of this disease. A culture injected into the blood-vessels of a chicken or rabbit develops the characteristic symptoms. Guinea pigs, however, are said to have immunity.

In diphtheria a bacillus and an enzyme are found. The bacillus is in the diphtheritic membrane, but not in the blood of diseased organs. The cat, cow, and Guinea pig are liable to the disease if inoculated with the bacillus.

In typhoid fever, the bacillus typhosus; found in Peyer's glands, spleen, larynx, lungs, liver; sometimes in kidneys and urine, and in blood. The disease has been reproduced by inoculating pure cultures. The stools of patients are highly infectious and should be disinfected before being thrown away. Mercuric chloride or ferrous sulphate may be used for this purpose.

In malaria the bacillus malaria is found in the spleen and marrow

in the form of threads and spores. The microbe was first discovered in the soil of the Roman Campagna. It flourishes in marshy districts, deltas, alluvial soils, and banks of tropical rivers. It is found abundantly in the blood in malarial diseases, and is said to be inhaled, but may perhaps be taken up by the skin or stomach. It is wafted by winds, floating about six feet above the ground, and is stopped by mountains and belts of trees. An amoebiform organism has also been found in the blood in this disease; if injected into the veins it gives rise to intermittent fever.

In glanders or farcy the bacillus mallei has been found in the lungs, liver, spleen, and nasal membranes of horses, sheep, and men Idead of the disease.

In leprosy, the bacillus lepræ. The disease is both contagious and hereditary. If the cultures are introduced into the system of an animal they produce the disease. The disease is common in parts of Africa, South America, Southern Asia, and some of the Pacific islands. It is incurable.

In tuberculosis or consumption, the bacillus tuberculosis is found in sputum, blood, tissues, urine, etc., and in the tubercles themselves. Inoculated in animals, it produces the disease. The bacillus forms cellulose from the tissue. Not only man, but the cow, goat, sheep, horse, pig, carnivorous animals, fowls, and rodents are susceptible. It grows more readily in animals which are omnivorous or herbivorous. Galtier says that cheese and whey from the milk of tuberculous cows often contain the bacilli. Swine and poultry fed on these dairy products often develop the disease. Their flesh in turn may give the disease to man.

The expectorated matter of tuberculous patients is highly infectious, even after having been dry for several months. The bacilli may enter the system by breathing or swallowing, or directly by a scratch or cut. Boiling milk and thorough cooking of meats of animals suspected of having the disease destroy the bacillus. Persons suffering with the disease should sleep by themselves, for many have contracted it by occupying the same bed with a patient. All causes which weaken the constitution increase the susceptibility and hasten the progress of the disease.

In anthrax or malignant pustule or splenic fever the bacillus anthracis is found in blood and tissues of animals, and causes the disease. Those who handle the hides, wool, or hair of animals dead of the disease are liable to contract it, either by breathing the

spores or by a wound in the skin. The animals should be cremated. It is said that the bites of fleas can carry the infection. Animals grazing on the land previously occupied by diseased animals are liable to be infected.

In swine fever a bacillus is found in lungs, spleen, liver, intestine, and serous membranes of pigs dead of the disease. Inoculations of pure cultures produce the disease in those susceptible, as pigs, rabbits, mice, and pigeons. It may be so cultivated as to be modified. When this modified form is inoculated the animals become proof against a fatal attack.

In Asiatic cholera the bacillus cholera or comma bacillus is always found in the rice-water stools of patients sick or dead of the disease. In tetanus, bacilli which produce spores. These inoculated in mice and rabbits reproduce the disease.

Yellow fever spreads by means of moist winds and human intercourse. Water and soil seem to have nothing to do with it. It prevails in plains near the sea-coast and along the course of great rivers.

Cholera follows the course of rivers. A moist atmosphere and soil are necessary. Moist winds are the great agents of distribution. Troops, pilgrims, and emigrants spread the disease far and wide.

Malarial diseases are more prevalent in moist than in dry weather. Moisture in the soil is necessary to their production; clayey, loamy, marshy soils favor the development. In marshy districts the larger the amount of organic matter in the soil, the greater the amount of malaria. The lower the level of the country, the more prevalent the disease, although in Central Africa a height of 2,500 feet is not free from it. Air, water, and food may convey it.

In conclusion, I would remark that the discovery of these microbes, the study of their life history and products, and their causative and other relations to disease have done much to simplify treatment. Generally speaking, these diseases run a definite course, which can be but little, if at all, shortened by any treatment. The treatment is, therefore, directed towards making the patient comfortable, keeping up his strength, preventing complications, controlling his personal hygiene and his surroundings, and in other ways avoiding death and promoting recovery. This is the true idea of cure, which is to take care of. The mortality is much lessened; the consequences are much less serious.