divide the cattle into three groups each containing 7,000,000 cows. The actual results are as follows:

Uncle Sam's Three Herds of Dairy Cattle

The first herd is kept at an actual loss of $7.25 per cow, while the first and the second herd combined yield a profit of only thirty cents each and the cows of the second herd must be milked 82 times for each dollar of profit. The third herd is really the only profitable one. When such facts are fully realized we may anticipate marked improvement in the quality of cows kept.

In at least one other way hitherto unmentioned are animals helping man. This is with reference to germ diseases. The beginning may be dated in the last decade of the eighteenth century when Edward Jenner, noting the pure complexions and smooth skins of the milkmaids wondered if the chance infection with cowpox prevented their taking the dreaded smallpox. Experiment proved this to be true. Now with the elimination of cruelty and needless suffering investigators the world over are trying experiments upon lowly forms of life to see if in some way control may be gained of the germ diseases which cause so much suffering and death among mankind. The results have been wonderful.

In the natural world there is no such thing as natural death in the sense of the long sleep coming after a long life with the gradual weakening of the vital powers. Death is the result of accident or assault by some foe in

• FRASER, W. J. Three Herds Dairy Cattle, Rev. of Rev., March, 1915.

numbers large or small. Now that the large animals are overcome man is tempted to boast of his conquest, forgetting that today his dangerous enemies are the minute forms of life. The discovery of the causes of zymotic diseases and the various methods of fighting them makes the contest hopeful.

Soon after the microscope came into use in the seventeenth century, Leeuwenhoek (1687) discovered the minute one-celled plants known as bacteria. In 1762 Plenciz, a physician of Vienna, suggested that diseases were due to such animalcules, each disease having its own. This theory had some vogue; but no one seems to have tested the suggestion so the idea quickly died out. In 1837 an Italian, Bassi, discovered that the disease killing the silk worms was apparently caused by "minute glittering particles" of matter that passed from the sick to the healthy. About 1860 Pasteur found germs in the air. In 1849 Pollender saw rod-like forms in the blood of cattle afflicted with anthrax, but it was not till 1863 that Davaine proved that these were the cause of the disease. In 1880 Eberth identified the bacillus producing typhoid. In 1881 Koch found the bacillus of tuberculosis and in 1883 that of Asiatic cholera. The next fifteen years brought the discovery of the causes of many of the common diseases. The last fifteen have been less productive, with some notable exceptions, such as the solution by Noguchi of the cause of rabies in 1913. It is thought that the relatively few recent discoveries may be due to the fact that the undiscovered germs may be too small to be found with present instruments and methods. It is claimed that we know some 1500 varieties of germs, of which some 50 are causes of disease.

At first these discoveries were received with extreme

But the tests self-imposed

credulity even by medical men. by Koch left little doubt. He stated that before we could be sure that a given germ was responsible for the disease it was necessary, (1) to find it present in large numbers in every case, (2) to take it and make a pure culture in some substance, (3) to inoculate a subject with the pure culture and produce the disease, and (4) to find again large numbers of the germs in the inoculated subject. Today it is generally believed that all the diseases we call contagious or infectious are caused by minute organisms. Other forms of disease, affecting the individual only, result from shock or injury, from the presence of some chemical due to defective metabolism, or from some parasite like the tapeworm.

Inasmuch as these zymotic (germ) diseases are produced by plants and animals, it is possible to study them, learn their life histories and thus take measures to prevent their spread or to fight them in the body of the sick animal or person. With few exceptions there are no specific cures for these diseases, that is we do not have substances which we can use in such fashion as to kill the germs causing distress to the human body without killing the person. To this statement there are today a few exceptions, true in most cases at least: malaria can be cured by quinin; iron overcomes certain types of anemia; while syphilis yields to arsenic and pyorrhea to ipecac. It may be that future research will reveal other such specifics.

Knowing the nature of the causes gives man other avenues of attack. Inasmuch as given plants use certain elements as food, it must follow that those elements in a given person may be exhausted. If then some similar organism can be found whose after-effects are mild, the soil may be rendered unfertile for the dreaded disease,

which cannot develop thereafter even if it finds entrance. Or, it may be that the poisons produced by such related forms destroy the later comers. We have not yet discovered the germ of smallpox, but the milder cowpox gives almost complete immunity. In other cases we use the self-created poisons above mentioned (called antitoxins) and, by injecting these into the system, as in diphtheria, destroy the disease.

To tell the story of man's failure and success in the battle with disease would require many volumes. We can only give a few illustrations here and indicate future possibilities. In 1867 Lister, seeking to cut down the terrific death rate following surgical operations, used carbolic acid with surprising results, and thus started modern antiseptic methods. Anesthetics had already been introduced. Ether was first used by an American physician, Dr. C. W. Long, in 1842. It came into general use in 1846 and in 1847 chloroform was employed. Thanks to these and present methods of operating, openings of the head, chest and abdomen which were considered almost necessarily fatal in 1870, and only done when death was otherwise certain, are now practically without danger.

The mortality of ovariotomy formerly 69 per cent is now 2 per cent. The mortality of compound fractures formerly 60 per cent is now 3 per cent. The mortality of major amputations formerly 50-63 per cent is now 10-20 per cent.

For many years the death rate of women at the time of childbirth was most puzzling. "Le Fort, in his railing accusation against the lying-in hospitals of France, which appeared in 1866, calculated that 30,394 deaths from puerperal fever had occurred in the 888,312 women delivered in the hospitals of Paris up to the year 1864 - an inci

dence of 3.5 per cent, or one death to every 27.2 labors. Moreover, he stated that from 1860 to 1864, inclusive, the mortality in the Maternité of Paris was 12.4 per cent, which in December, 1864, rose to the colossal height of 57 per cent, while in the Clinique it averaged 14.7 per cent between the years 1833 and 1864, and on several occasions rose above 20 per cent. On the other hand, the mortality outside of the hospitals was much less, as only one woman perished out of every 212, which indicated that seven-eighths of the hospital deaths were due to conditions prevailing in them." In Germany 3.4 per cent of those in hospitals died, but only .6 of those delivered at home. England showed similar conditions. In the United States the Pennsylvania Hospital had a record of 5.6 per cent from 1803 to 1833. In an epidemic at Bellevue Hospital in 1872 the death rate rose to 18 per cent. Today, thanks to antiseptic methods, the death rate in good hospitals is less than .25 per cent. Investigation revealed the fact that this death rate in the hospitals was due to germ infection. Once the fact was discovered, efforts were made to meet the situation with excellent results. Thus in 1909 the New York Lying-in Hospital lost only .34 per cent out of 60,000 obstetrical cases, or one out of 1250.8

cure.

Now that we understand the nature of diseases somewhat, our problem becomes one of prevention rather than That vast unreasoning fear of disease which man had, and still has in part, largely disappears as we come to know the condition under which disease is dangerous. We know just how certain diseases are spread, hence we can safeguard ourselves.

7 WILLIAMS, J. W. Obstetrics and Animal Experimentation, p. 5. 8 KEEN, W. W. Animal Experimentation, p. 256.