It is also interesting to note that London, whose milk supply is more largely Pasteurized than that of other English cities, has but half the infant mortality rate from abdominal tuberculosis, although it has a death rate in excess of other urban districts from other tuberculous diseases.

To keep this paper within prescribed limits one must pass to other features of the subject. The greatest saving of infant life in recent years has been in connection with cases of diarrheal diseases. Comparing 1921, when the summer temperature was higher and more prolonged than in the other two abnormally hot years of the century, viz, 1906 and 1911, the decrease in the diarrheal death rate of that year, as compared with 1911, represented a saving of 13,725 lives. As regards pneumonia, there appears to be no decrease of the death rate since the beginning of the century. It is too soon to say whether the marked decrease in bronchitis mortality shown in 1921 is permanent, but it is encouraging, as also is the great and steady decrease in deaths from convulsions. With this grim quartette we must come to grips if we would banish the worst ills of infant life.

What is the infant mortality from bovine tubercle, of something like 1 death to 4,000 births, to compare with that of this group, which accounts for from a quarter to a third of all infant deaths? Is there then any common condition which accounts for them, and bearing in mind the object of our inquiry, is milk responsible; and if so, how?

Dealing with the latter part of this question first, it is difficult in the present day to secure evidence which is not affected by the great advance in the practice of Pasteurization, which excludes many potential dangers from the milk supply, and reduces others, and also by the widespread use of dried milk by the wage-earning class, which suffers most of the infant mortality. But, fortunately, evidence exists from a day when either of these factors had little if any influence on vital statistics in Great Britain. I quote from official documents of the British Local Government Board.

In the year 1908, Dr. Meredith Richards, its medical officer of health, wrote of the large town of Croydon:

It is impossible to define social status very accurately, but for some time past it has been our custom to divide the births in the borough into two groups, namely, those occurring in large houses and those occurring in small houses. Generally speaking, every tenement of six rooms and over is considered a large house. Adopting this more or less artificial grouping, it is found that during 1908 there were 1,113 births in large houses, and of these only 49 died, a rate of 44 per 1,000, as compared with 2,884 births with 349 deaths in smaller houses, a rate of 121 per 1,000.

The milk used by either group would be of the same general character. There is no doubt that the class living in larger houses would use more of it, and if milk was necessarily the cause, would suffer a greater mortality. But there is more than that in it. As the report to the local government board remarks in this connec

tion:

This is the more instructive, in view of the fact that probably 80 per cent of the mothers of infants in wage-earning populations suckle their infants partially or entirely; and the proportion of mothers in well-to-do classes who are able or willing to continue to give their infants this immensely important start in life is believed, I think rightly, to be much smaller. There must be

reasons of great potency, enabling infants of the well-to-do to survive in much higher proportion to the end of the first year of life, notwithstanding this heavy handicap against them.

The foregoing refers to 1908. Let us go back still further, to a time when milk hygiene was still more rudimentary, to a time and place where Pasteurization and similar safeguards were practically unknown. In the year 1904, Dr. John Robertson, the medical officer of the city of Birmingham, recorded an investigation into every death in the city from infant diarrhea. It was found that practically all these deaths occurred in small houses occupied by the artisan classes. No deaths occurred in any middle-class or betterclass house during the time of the inquiry. Some few deaths did occur in houses of over five rooms, but in each of these cases there were special circumstances which brought them within the meaning of artisan houses.

Here, where a milk supply of the same general character only was available, it was found that 100 per cent of the deaths from the cause most fatal to infants all over the world occurred among children of a particular class, and that the children of another class using the same milk suffered no deaths at all-and this in spite of the handicap of a lessened proportion of maternal feeding.

Diarrhea disease is perhaps the most deadly enemy of the children of the poor, but it has other and venomous allies. The same circumstances that provide the greatest number of diarrhea deaths, at another period of the year cause most of the deaths from pneumonia and bronchitis, these two diseases, which are linked together in occurrence with infant diarrhea, accounting for nearly 20 per cent of all infant deaths. Have they a common cause, and above all, is it milk?

Obviously it is not due to farm and dairy infection of milk. Neither, it would seem, is it due to the exposure of loose milk in the open street during delivery, since, were these the controlling factors, the result would be manifested in the death of children of every class alike. Tests made repeatedly in London show that the bacterial increase in loose milk delivery to the consumer is very small-provided that it be delivered from properly sterilized vessels-but that the increase in the home, where the milk is kept in ordinary jugs or other domestic vessels, is very great. One has not the space to quote many authorities, but the names of Sir Arthur Newsholme and of Sir George Newman command respect the world over. In his work on Infant Mortality Newman writes:

Newsholme again points out that the evidence obtainable is all in support of domestic infection of milk rather than farm infection of milk. If diarrheal infection came from the farm we should expect three events which we do not obtain. First, there would be massive infection. Secondly, there would be the ordinary characteristics of milk-borne epidemics. Thirdly, there would be a higher incidence of fatal diarrhea among infants fed on fresh milk than on condensed milk. Not one of these characteristics do we obtain. * * It is the condensed-milk fed infants that mostly die from diarrhea, not because condensed milk contains more organisms than fresh cow's milk (for it contains less), but in all probability because condensed milk is less nutritious and sustaining, and is more liable to home contamination than cow's milk.

Elsewhere Newman remarks:

It can scarcely be denied that the evidence that diarrhea is due to domestic infection is overwhelming.

If further proof be required of this, it is found in the fact that the use of dried milk, in spite of other disadvantages, has been attended with a greatly reduced mortality from diarrheal and attendant infections. It is not that it is a better or as good a food as fluid milk, but the fact that it is dry until about to be used eliminates the danger of domestic infections which are so fatal. I will conclude. this part of my paper with two quotations from Newsholme, the one from his report to the local government board on "Child mortality' and the other from his Public Health and Insurance:

Towns with a high total child mortality have a high mortality from diarrhea, and from bronchitis and pneumonia. This and other facts point to the conclusion that these diseases are fostered by the insanitary conditions of the home and its surroundings.

If pneumonia and bronchitis, which account for 19 per cent of deaths in infancy, be regarded as they should-as infective diseases-then it may be said that the problem of saving child life and securing the correlative improvement in the standard of health of children who survive to higher ages, consists very largely in the prevention of infections including diarrheal disease and acute respiratory diseases.

The foregoing all shows that, as at Croydon, the class using even the ordinary milk of commerce most liberally only suffered a rate of infant mortality approaching the most sanguine hopes of reformers, and that so far as milk is responsible for sickness it is overwhelmingly due to domestic infections and not to farm or dairy contamination.

The great value of Pasteurization in securing the purity and safety of the milk supply has already been acknowledged. It frees milk at once from the fear of tubercle and other epidemic diseases, as well as many obscure and mysterious troubles. But neither Pasteurization considered by itself, nor any better and cleaner method of production, will even touch the great causes of infant sickness, because these are things that are apart from the cow, the farm, or the dairy, and belong to the home. The enemy of man is man. As Sir George Newman wrote:

It is not external environment which primarily affects the infant mortality, and produces that prematurity, pneumonia, atrophy, and much of the diarrhea which occur in infant life. The things are produced by some evil condition or conditions in the habits and homes of the people, which are, after all, the vitals of the nation.

The problem is how to protect the marvelous qualities of milk from the moment of delivery until it is consumed. Protect it from the infections which abound under certain conditions in the home of mankind-infections which are powerless against older people but to which the infant readily succumbs. The answer is contained in one word, "insulation." The beneficent influence of Pasteurization applied to milk has been beclouded by the failure to regard the influence the practice of bottling this Pasteurized milk has in protecting it from the subsequent and greater dangers which come from human infections. In those cases where systems of sterilization of milk have been organized by commercial, municipal, or philanthropic bodies, the credit for much of the good results obtained should be given to the insulating virtues of the bottle.

Where lies the purport of all this? Here. Tell the mother of a sick or dying baby that her child is ill because of something that happened on a far-away farm and she can do nothing but weep help

less. despairing, and rebellious tears. But tell her that the trouble is due to her own household, perhaps to her own hands, and show her how, with a little care, a little knowledge, and a little help the trouble can be prevented and her child raised to health and strength, and you fill her heart with happiness and hope, and with a purpose to guard her child from the enemy till then unknown. That American cities have so generally insisted on the Pasteurization of milk is to the credit of their civic intelligence. But so far as they fail to insist on the insulation of this good Pasteurized milk by universal bottling in sterile bottles, it is a ruinous debit. It is a debt that weighs the scales ruthlessly and hopelessly against the child. In the past, attention has been riveted on the cow, the farm, and the dairy. Let us get back to the home and show the mother that it is there that the child's life and health are won or lost; that the problem is more moral than material. And let us insist that in part the burden of pro protection be lifted from her weary hands and straightened means by giving her a milk which by Pasteurization and insulation is guarded from all save heartless carelessness and hopeless ignorance. So shall we best help to bring to pass the vision of the prophet looking for the new Jerusalem where "there shall be no more an infant of days, nor an old man that hath not filled his days, for the child shall die an hundred years old."

Chairman WELD. The next paper, the subject of which is "The relation of the melitensis-abortus group of organisms to human health," is by Miss Alice Evans. I regret very much to announce that Miss Evans can not be present. She is the bacteriologist of the United States Public Health Service; she is seriously ill, having contracted Malta fever as a result of her experimental work with this disease. Her paper is here, however, and if it is the desire of the body it will be read by the secretary, Doctor Roadhouse.

Mr. H. R. ESTES (Flint, Mich.). I move that the paper be read at this time.

(The motion was seconded by Doctor Hastings, of Toronto, and carried. Secretary Roadhouse read Miss Evans' paper.)

THE RELATION OF THE MELITENSIS-ABORTUS GROUP OF ORGANISMS TO HUMAN HEALTH.

Miss ALICE C. EVANS, associate bacteriologist, United States Public Health Service, Hygienic Laboratory, Washington, D. C.

It is a curious circumstance in the history of bacteriology that during the greater part of its existence as a science it has recognized under two generic names, organisms which, since a comparison has been made, are now taxing the resources of investigators to find distinguishing characteristics. Both of these organisms have long been well known, the one being the so-called Micrococcus melitensis, causing Malta fever in man, and the other the so-called Bacillus abortus, responsible for contagious abortion in cattle.

Malta fever, known also as Mediterranean or undulant fever, is widespread in subtropical regions, and presents an important health problem in countries of the Mediterranean littoral, in South Africa,

and we may add, in the State of Arizona in our own country. This disease exists also in India, China, and the Philippines, and it has been described in Peru. It has been said that Malta fever does not occur in Europe north of 46° latitude. There is, to be sure, no such definite boundary. Occasional outbreaks have been known to occur farther north. It is a fact, however, that in southern Germany, Hungary, Switzerland, and Czechoslovakia goat's milk is commonly used without the prevalence of Malta fever similar to that in neighboring countries to the south.

The causal organism of Malta fever was discovered by Bruce as early as 1887. Twenty years after this discovery, the British Commission for the Investigation of Mediterranean Fever published a report, in which it was definitely established that infected goat's milk is a common source of human infection. They found that infected goats generally evinced no symptoms of disease, although melitensis might be multiplying in the udder with the excretion of great numbers of the organism in the milk. Following the publication of this report the British Army and Navy forbade the use of goat's milk among their troops, with the result that Malta fever, which formerly had been a serious disease in causing a large percentage of men to be incapacitated for duty, was practically elimiated. The eradication of Malta fever from the British troops is one of the notable achievements of medical bacteriology.

By

The British commission established also that various other domestic animals became infected with the Malta fever organism. testing the agglutination reaction of the blood serum, they found infected cows, mules, dogs, and cats. In none of these animals did they find symptoms of acute disease.. It is notable that they found that the milk of infected cows, like that of goats, contained the Malta fever organism.

Ten years after Bruce had discovered the so-called Micrococcus melitensis, and ten years before the publication of the monumental report of the British Commission for the Investigation of Mediterranean Fever, Bang, in Denmark, discovered the causal organism of that serious disease of cattle, namely, contagious abortion. He named his organism Bacillus abortus. Bang had no reason to suspect a relationship between his organism and that causing Malta fever. He had no evidence that Bacillus abortus infected human beings. Moreover, his organism was a rod form, a bacillus, whereas the Malta fever organism was designated a micrococcus. That generic name micrococcus was destined to obscure the relationship between the Malta fever organism and that of contagious abortion for more than 20 years after Bang's discovery. The name stood as a guide post misdirecting bacteriologists to make no comparison of "Micrococcus melitensis" with any bacillus. We now know that the Malta fever organism is a rod form, and that the name micrococcus was a mis

nomer.

It was not until the year 1917 that a comparison of the two organisms was made. At that time I was working in the Dairy Division of the Department of Agriculture, and one of the problems that had been assigned me was a study of the bacterial flora of cow's milk drawn aseptically from the udder. It was found that, together with streptococci and staphylococci, there are commonly present in cow's