The ratio between the normal and abnormal flowers was found to be a function of the environment. Under a given set of environmental conditions this ratio as well as the relationship between the different forms of abnormal flowers inter se is constant to a very marked degree.

Selection carried out for five years had no visible effect upon the type and range of floral variations of this race. The ever-sporting strain after isolation at once displayed the highest degree of abnormality ever reached in the subsequent generations under similar conditions of environment. Under conditions controlling the intensity of abnormal development, optimum nutrition or starvation, while affecting the habit of the plant, appeared to have no effect upon the degree of manifestation of floral abnormalities. The evidence from the study of this race under different conditions of environment points to high humidity and temperature as the factors favoring the expression of abnormality. Under conditions void of optimum humidity and temperature, the influence of starvation and lack of water upon the degree of abnormal development was noticeable.

The results of a study of the frequency distribution of the different types of flowers upon the plant point to the existence of a definite region on the plant in which the tendency to vary and proliferate is most pronounced. Considering the plant as a whole, this region is confined to the basal, differentiated parts of the plant. The frequency distribution given in table 4 shows that the first three branches on the main stem from below, especially the second one, mark the seat of greatest abnormal development while the racemes in the axils of the 4th, 5th, and 6th branch show a low degree of variability as well as the lowest absolute number of flowers.

Similar but more marked differences prevail in the individual branches of the second and third order. Here it is again the buds in the axils of the second leaf and in the basal region of the terminal raceme that show the greatest relative number of abnormal flowers as well as the greatest range of variability as measured by the frequency occurrence of the most aberrant variants.

Relative to the frequency occurrence of the different types of flowers at different periods of the flowering season, under the conditions prevailing in the greenhouse the first and second week of the flowering season mark the lowest relative production of abnormal flowers, after which a marked increase in the output of abnormalities follows when the secondary and tertiary branches begin to develop their flowers. Towards the end of the flowering season the upper regions of the plants produced only

TABLE 4

ACTUAL AND PERCENTAGE FREQUENCY DISTRIBUTIONS OF FLOWERS BORNE BY EACH ORGAN OF EACH PLANT, WITH RESPECT TO NUMBER OF CARPELS

very few flowers while the lower differentiated parts of the plants sustained their flower production to the end of the flowering season.

Floral prolifications in the form of various types of synanthous flowers, often giving rise to syncarpous fruits, were found to be transmitted from generation to generation in fairly constant proportions under given conditions of environment.

The teratological development of the vegetative organs appeared in the form of more or less developed fasciations. Fasciated branches were first discovered on the plants of the fourth generation grown under crowded conditions, in pots. In the next generation, under favorable conditions of nutrition, the fasciated character asserted itself in a manner typical of the ever-sporting races the fasciations being reproduced by half of the progeny.

THE EFFECT OF MILLING ON THE DIGESTIBILITY OF GRAHAM FLOUR

BY C. F. LANGWORTHY AND H. J. DEUEL

OFFICE OF HOME ECONOMICS, U. S. DEPARTMENT OF AGRICULTURE

Communicated by W. A. Noyes, October 14, 1919

The bulk of wheat used for flour in this country is made into patent flour which contains about 72% of the wheat kernel. Entire or wholewheat flour which contains 85% of the wheat and true Graham flour which contains 100% are also we 1-known commodities.

The digestibility of patent flour is considerably higher than that of entire-wheat or Graham flours. An average' of 31 tests by other investigators with patent flour shows that the coefficient of digestibility for the protein is 88.1% and for carbohydrate 95.7%, while an average of 43 as yet unpublished tests made in this laboratory2 on patent flour gave the coefficient 89.5% for the digestibility of protein and 99.9% for that of carbohydrate. An average1 of 23 tests of the digestibility of entire-wheat flour (85% extraction) gave the coefficient 81.9% for the protein and 94.0% for the carbohydrate while an average2 of 16 tests on similar flour by this office2 gave the coefficient 87.1% for the protein and 98.3% for the carbohydrate. The average1 of 24 tests on true Graham flour was 76.9% for protein and 90.1% for carbohydrate and an average of 33 experiments on the same flour by this office2 gave the value 84.2% for protein and 94.4% for carbohydrate.

It has been a question as to how the milling of Graham flour effects its digestibility. Wheat milled by different processes gives bran particles varying in size from the very small ones obtained with a burrstone mill to very large ones with a roller mill. The method of milling also effects the extent to which the walls of the aleurone cells are broken or weakened. These, if intact, prevent the digestion of their contents, and so the more they are broken the more completely are the nutrients of the flour digested. Lapicque and Liacre3 found that kneading the bread broke the aleurone cell walls at points weakened by the milling process. Obviously, the method of milling would affect the extent to which the walls of the aleurone cells would be weakened. The experiments here reported were undertaken to determine how different methods of milling effected the digestibility of Graham flour.

The flours were all made from a single lot of Minnesota spring wheat secured through the courtesy of the Plant Chemical Laboratory of the Bureau of Chemistry. Portions of the wheat were ground by the following methods: (1) Small laboratory roller mill, (2) commercial roller mill, (3) burr-stone mill, (4) steel-burr mill, (5) steel attrition mill.

The portions of flour milled on the laboratory roller-mill, the burrstone mill, and the steel-burr mill were prepared on the m lls of the Plant Chemical Laboratory, Bureau of Chemistry. The commercial rollermill flour and the attrition-mill flour were prepared by two commercial

concerns.

As was the case in many other tests in this laboratory, the flour was fed in the form of a simple 'quick bread,' which was baked each day. A little ginger not only added to the palatability but masked any differences between the breads in the different tests. The following recipe was used:

The lard was added to the hot water, this mixture was added to the other ingredients. This was thoroughly mixed and baked for 1 hours.

With a generous portion of the bread a simple basal ration of fruit (oranges), butter, and sugar, with coffee or tea without cream, if desired, was eaten. The tests were of three days or nine meals duration. The separation of the feces, analyses, etc., were those usually followed.

The subjects were young men, twenty to thirty years old, students in a local university, in good physical condition, familiar with this type of work, and entirely trustworthy.

Granulation tests made with the different flours showed the following percentages remaining on each sieve.

Results of granulation tests with different Graham flours

It will be noted that the flour from the laboratory roller mill was the coarsest, while the stone-burr mill gave the flour of the greatest fineness. In this table and those that follow the flours are given in the order of their size from the coarsest to the finest.

The condensed results of the experiments appear in the tables which follow:

Average amount of Graham bread and total food eaten per man per day