The average European merchant in hot countries keeps his own cow, and one has often been consulted by an anxious mother who has been unable to understand why the milk of this home-fed animal disagreed with the children or why they were not thriving on it. She has failed to see that the mammary secretion under tropical skies must lack the essential "goodness" which we now know to be due to the presence or absence of vitamins derived from the animal's own food supply. It is on' by improving the pasturage and the supply of ample green food that the milk of tropical milk cattle can be improved and made a reliable food for growing children. The difference is striking even between the milk of native and imported cattle, and I have seen a child going from bad to worse while fed on its parents' "own cow," rapidly improve when put on the milk of a recently landed Australian animal.

The average consumer of milk in the tropics is almost as careless with regard to the storage of milk in the household as the milkman is often criminally negligent in its collection and distribution. Among the well-to-do classes the care of milk is more often than not left to ignorant and dishonest servants. The first duty of the consumer is to see that a responsible member of the household personally attends to all details with regard to the transit of milk from pasture to pail and from pail to palate. All milk should be scalded at the earliest possible moment, as we now know that the nutritious qualities of milk do not materially suffer by heat, and it is a remarkable fact that the natives of India who live largely on milk never by any chance consume it raw. Having been boiled, the milk must be carefully stored, as it is useless to attempt to sterilize the milk and then permit reinfection by dust and flies.

Pure milk produced from well-fed cattle and kept clean until its consumption is the ideal to be aimed at, but in the Tropics this ideal seems unattainable at present. It is little wonder, therefore, that the physician and sanitarian have turned with relief from the white sewage nicknamed "milk" to the attractive substitutes which have been placed on the market. Condensed milk was the first of these milk modifications, and its popularity was eloquent testimony to the demand for some substitute for the local product. For tropical use the keeping qualities of condensed milk are not much superior to fresh milk, and the large proportion of cane sugar in the sweetened variety renders it undesirable as an infant's food, and most unpalatable to most adults. Some 15 years ago my attention was drawn to a form of dried milk which since that time has steadily advanced in public favor. I carried out a series of experiments and analyses on behalf of the Government of India and formed such a favorable opinion of the product that I have ever since advocated its adoption for tropical use, and am in agreement with Professor Dreyer, of Oxford University, that it may present us with the best solution of the milk problem. To quote from the professor's paper at the National Milk Conference in London last October, 1922:

Dry milk will keep for some months; it is very easy to manipulate cleanly in the home; there is little or no wastage from souring, etc.; it does not appear to be inferior to raw milk for feeding. (Report of National Milk Congress, p. 158.)

In the discussion which followed a paper on "Dried milk as a food" which I read before the Birmingham Congress of the Royal Sanitary Institute, 1920, the speakers agreed that they had never seen a case of rickets or scurvy in a child fed on dried milk, and as these speakers were mostly medical officers of health of important towns their evidence must be regarded as conclusive.

The position of waterless milk as an infant's food in the Tropics may be summarized as follows:

All authorities are agreed that it is eminently suited for warm climates and the well-known tropical physician, Doctor Harston of Hongkong, emphasizes the advantages of dried milk over condensed milk in China.

Dried milk is superior to fresh tropical milk in nutritional value and especially adapted to supplement breast feeding.

All experience shows that dried milk is more digestible than fresh milk, and it is therefore indicated in digestive troubles. I have found it of special value in infants who have been doing badly on other milk preparations and have seen rickety children steadily improve on dried-milk diet.

Dried milk has a wide field of usefulness as a food for adults and invalids in the Tropics. The United States Department of Agriculture has in its valuable pamphlet, "The use of milk as a food," pointed out that "milk should not be regarded as a luxury but as an economical article of diet which families of moderate income may freely purchase as a means of improving the character of the diet." This should be more widely known in the Tropics, where the European resident constantly complains of the poor quality of animal foods but nevertheless drinks little or no milk.

I have found dried milk an excellent food for nursing mothers and have had considerable experience with it in sprue and chronic dysentery. I have seen this form of milk extremely well tolerated in cases where ordinary cow's milk was badly borne and while acting as consultant in tropical diseases to the Ministry of Pensions in London I have prescribed it with success to pensioners in the later stages of these diseases.

The chief reasons which have influenced me in using milk powders in cases of chronic diarrhea and dyspepsia have been: The fine flocculent clot; the fact that dried milk can be digested in strong concentration. The chief objections to ordinary milk, namely, its bulkiness and its hard curd, are thus surmounted.

During the discussion on my paper at the Royal Sanitary Institute the medical officer of health of St. Helens spoke very highly of the value of dried milk in the dietary of typhoid fever. In my own experience, dried milk solves the difficulty of presenting a milk diet in an attractive and constant form to the subject of an acute specific fever. Samples of ordinary tropical milk vary immensely in their composition, as I have shown above, whereas dried milk from a reliable firm consists of milk solids in an invariable proportion. It is thus possible to prescribe milk with approximately the same accuracy that one prescribes drugs.

In view of the defects I have pointed out in the supply of fresh milk for use in the Tropics or in places such as Malta, where cow's milk is obtainable and goat's milk dangerous, dried milk has a wide.

range of application, while on long voyages, on hunting or exploration trips, it presents many advantages over condensed milk. Produced and dried under the excellent conditions attained by some manufacturers from milk of cows fed on rich pasture, it contains the essential "goodness" that Sir James Cantlie and other writers have insisted on; and on the whole, from long and varied experience of its use in war and peace, I am inclined to agree with the opinion of Professor Dreyer, that waterless milk presents the only solution at present available to the manifold problems which I have indicated as associated with milk in the Tropics.

Chairman CUMMING. The papers are now open for discussion. Capt. JOHN GOLDING (National Institute for Research in Dairying, Reading, England). I want, in the first place, to express my indebtedness to the committee of the World's Dairy Congress for the opportunity which they have given us to meet face to face so many of the pioneers in this new work on the nutritive value of milk. It gives me great pleasure, and I feel compensated this morning for the long journey from England.

I just want to ask Professor McCollum one question, and that is whether in his observations on the children he told us about this morning he included any treatment in connection with rickets. whether the rickets which were obvious in some children cleared up with the treatment by use of milk, and whether there are photographs showing this.

Doctor MCCOLLUM. The demonstration of which I spoke was carried on about four years ago. We were limited as to funds, and it was only with difficulty that we secured any medical cooperation in the work, because that could be had only if paid for. Our medical observations on these children were, therefore, limited to a single systematic examination at the close of the demonstration by Doctor Ayd. It did not include any observations on the improvement of rickets in any of the children. Our observations were limited to the growth response, where that existed, and to the behavior of the children.

One of the striking things about the whole experience is that the children of this institution were very well-behaved. Discipline had never been a problem. They were meek, inactive, lethargic. Within a few weeks after we began our demonstration those in the group who were given the whole-milk additions to the diet began to be active and made some trouble for their teachers. This change in their behavior was as striking as any feature of the demonstration. I regret now after four years, when we know so much more about rickets than we did at that time, when we gave so much attention to every detail we could take care of at that time, that more accurate observations on the bones of these children were not made. Chairman CUMMING. Is there any further discussion?

Prof. ROBERT WALLACE (University of Edinburgh, Scotland). I visited India in 1879. I am sorry to hear there is no greater improvement in the natural supply of milk in that country. It was then carried about in kerosene cans from one place to the other. There has been a movement in the breeding of cattle there. It has been found

that the Ayrshire breed mixes particularly well, although I want you to understand that I do not wish to advertise Ayrshire in preference to Holstein, but experiment has shown that the breed mixes very well with the cattle of India. The cattle of India, being exposed to the strong sunlight, have black skins. That is the great difference between the cattle of India and the cattle of European countries. That gives them health, which should enable them to produce good milk, if it is kept clean. European cattle have only half the strength of the cattle of India.

A man by the name of Smith has had control of dairy breeding in India and he has begun to develop this product of dry milk with the greatest of success. I am also glad to tell you that they have determined to sell a great deal of dry milk to Europe to help make up the deficiency of our supply of milk in the home.

The people here are all wrong in trying to breed white cattle. The hair of Ayrshire cattle is brown. They are not white cattle at all. When I was a boy there was not a single white animal in a hundred dairy cows. You are beginning to make the same mistake with your Holsteins as with your Ayrshires. They can not resist the effect of the sun if they are white. You will have animals that will blister in the sun and will be unable to give you the best quality of milk.

Chairman CUMMING. Sir Arnold Theiler, director of veterinary research in the University of South Africa, has now arrived, and I am sure he can give us some information in connection with these papers.

Sir ARNOLD THEILER. In connection with these various experiments which have been detailed in the papers read by these distinguished men, one thing has been overlooked, which I wish to mention which we in South Africa have for the last few years found to be one of the most important points in nutritional values, and to which we have given much attention. That is the supply of phosphorus. South Africa is very peculiar in the respect that the climate is dry. A large part of the country suffers from drought, this fact making it difficult to grow and develop food properly. As a result of this the cattle have a depraved appetite, which results in phosphorus deficiency and they develop a disease involving paralysis of the loins. If we supply the necessary phosphorus, not only the craving is appeased, but the animal changes entirely in its constitution. We grow a bigger animal and an animal with a better skin, a cow which produces more milk. These are things which in modern experiments on the Continent and in this country have been more or less neglected or overlooked. At this time, when so much is mentioned about nutrition, we should think of the mineral elements

Chairman CUMMING. Is there any further discussion?

Doctor McCOLLUM. I want to say a few words in appreciation of the very excellent paper presented by Doctor Bloch, of Copenhagen. He is one of the most eminent pediatritians in the world, and his paper deserves special mention. As a pediatritian he was able, through very close study of the conditions which he encountered among the children of Denmark, to arrive at conclusions as to the cause and treatment of a disease of obscure origin in children. His

observations were independent in great measure, although not entirely so, of the illumination shed upon the whole subject of nutrition in recent years by animal experimentation. His work on the eye diseases resulting from certain dietary faults is one of the great researches relating to human nutrition. It will always remain one of the classics of medical research.

Chairman СUMMING. I am sure we all regret very much that Doctor Pirquet was not able to be present. I know you will be glad to hear he has accepted a chair in the University of Minnesota. (Adjournment.)

(Papers read by title):

MILK AS A STANDARD OF NUTRITION.

CLEMENS PIRQUET, Ph. D., professor and director, children's clinic, University of Vienna, Vienna, Austria.

1. A "nem" is a nutritive, combustible value of 1 gram of average human milk. The name is composed of the initials of "Nahrungs Einheit-Milch," or "nutrition equivalent milk," and refers to a standard human milk of 1.7 per cent of protein, 3.7 per cent of fat, 6.7 per cent of milk sugar, as well as to a standard cow's milk of 3.3 per cent of protein, 3.7 per cent of fat, 5 per cent of milk sugar.

2. In spite of the great variations of the content of solids in the milk, we are entitled to take a certain theoretical average as a standard, just as we use the horsepower as a standard for our machines, disregarding the fact that every individual horse has a different

power.

3. The standard milk chosen has a simple relation to the caloric system, having 667 small available calories in 1 gram, or 667 large calories in 1 kilogram; 2,000 small calories (therefore, 2 large calories) equal 3 nems, or one large calorie equals 1.5 nems.

4. This milk unit is used as a metric unit, and is combined with the Latin prefixes for metric fractions, and with the Greek prefixes for multiples of the unit:

A decin m means one-tenth of a nem, or the nutritive value of 1 decigram of milk, 0.1 gm., and is written 1 dn. A centinem is written 1 cn., and represents 0.01 gm.

These smaller units are used only in the calculation of the food intake per square centimeter in its relation to the nutritional surface. In the practical use of foodstuffs we have to make use of the large units namely, the multiples with Greek prefixes: A dekanem (dn.) means 10 nems; a hektonem (hn.) means 100 nems. This unit is used in the composition of a recipe for a certain dish, or of the day's program for one person or family. A kilonem (kn.) means 1,000 nems. We use it in buying foodstuffs for a family, or making recipes for a large number. A tonnenem (tn.), finally, represents the food value of 1 metric ton of milk: 1,000 kn., or 1,000,000 nems. We use it in community nutrition.

5. The food values of all articles used for human food should be determined by substituting a given quantity of the article for milk. Meantime we use a chemical analysis of the food, discount the per