Four 14 to 19, year old boys are used as subjects in this study. The first part of this study attempts to investigate the vitamin C status of these subjects when they are consuming the ordinary diet served in the college staff dining room. The vitamin C content of the whole meal is determined by the dye titration method for ten days. During the first 2 days, blood samples are taken from finger tips and the plasma analyed for vitamin C by the Farmer and Abt method. 24-hour urine samples are also collected and the vitamin C content determined.After the first 3 days, in addition to the vitamin C in the diet, the subjects are subjected to vitamin C saturation by taking orally 400 mg of vitamin C form orange juice for two days followed by 5 days of 100 mg supplementation of crystalline vitamin C. Plasma vitamin C and 24-hour urinary vitamin C are ag(?) studied. Following this procedure, the subjects are considered ready for experimentation. They are put on an experimental diet similar to their ordinary d(?) but devoid of vitamin C. The vitamin C intake level is controlled. Three lev(?) are tried: 70 mg, 50 mg, and 30 mg daily. Each level is fed for 14 days. The vitamin C of the first seven days is provided by vegetables frequently used (?) Canton and crystalline vitamin C is used during the latter 7 days for comparison. Cantonese cabbage(Brassica chinensis L.), Kan Lan Tsai(Brassica alboclabia, R.) and Chinese celery cabbage(Brassica pekinensis, R.)are used for supplying vitamin C during the 70, 50 and 30 mg levels respectively. Plasma vitamin C and 24-hour urinary excretion are determined for the last 5 days of each period.The vitamin C content of the medical college diet averages 43.7 mg per day for the 10 days analyzed. Plasma vitamin C of the subjects ranges from 0.25 to 0.61 mg percent, averaging 0.37 mg percent. 24-hour urinary excretion varies between 3.3 and 74.8 mg daily.During saturation, plasma vitamin C of one subject increases after the first dose, while its content in the plasma of the other three subjects also shows gradual rise. Urinary excretions show immediate and considerable increases on the first day with each of the subjects.During the 70 mg vitamin C daily intake level, plasma vitamin C average 0.45 mg percent and 0.48 mg percent for Brassica chinensis, L. and for crystalline vitamin C respectively. Daily urinary excretions average 19.4 and 18.4 mg. for the two periods. When the vitamin C intake is reduced to 50 mg daily, an average of 0.40 mg percent of plasma ascorbic acid is found for Brassica alboclabia, L. and 0.32 mg percent for crystalline vitamin C. Urinary excretion decreases to 15.2 and 11.9 mg daily. At the 30 mg daily intake level, plasma vitamin C falls to 0.32 mg percent for Chinese celery cabbage and 0.31 mg percent for crystalline vitamin C. Total urinary vitamin C falls to 9.9 and 9.0 mg.The vitamin C from these 3 vegetables are at least as efficiently utilized as crystalline vitamin C.While it is not quite possible to draw definite conclusions in regard to vitamin C requirement of these subjects from the results of this study, there are suggestions however that a daily intake of about 50 mg of vitamin C may be able to maintain a fairly satisfactory state of vitamin C nutrition.

The first part of the work consists of thiamine analysis of 5 allotments of rice samples bought from retail shops in various districts in Canton from the end of 1954 to the beginning of 1957. Usually seven grades of rice are available, and the grades differ both in variety and extraction rate.It is found that the thiamine content of rice bought at the same time, or of the same grade bought within a few months may vary considerably. Two-third of the samples contain 0.11 to 0.18 mg of thiamine per 100 g of rice but it takes the range of 0.05 to 0.27 mg per 100 g to cover all the samples. With the exception of the lowest grade, the thiamine content in general increases with the lowering of grade and decrease of price.The second part of the work studies the influence of variety and of extraction rate upon the thiamine, niacin, riboflavin and protein content of rice. Seven varieties of rice commonly used for the seven grades extracted at different rates are obtained from a local rice mill by special arrangement with the City Food Bureau. 'Results show that milling decreases the content of these 3 vitamins and of protein, the decrease for thiamine and niacin being greater than for the other two nutrients. However, not only the original content of these nutrients in husked rice may vary, but also their degree of loss in milling may differ. Of the varieties studied the lowest grade of husked rice contains the greatest amounts of all the four nutrients while the "Super Grade A" tends to lose the least during milling. As a result, the milled products of these two varieties tend to contain slightly larger quantities of these nutrients.

A nutrition survey is made on some workers in a mine in Kwangtung during the winter of 1954. It is found that the workers come from different parts of China, but chiefly from Kwangtung with Shangtung and Liaoning next largest in number. The type of work varies from sedentary to heavy mining work. Workers eat in several dining halls of various types and they shift about as much as they like. Under these conditions, making dietary survey becomes a rather complicated undertaking.To facilitate analysis and tabulation of data, we have arbitrarily divided workers into southerners and northerners, the former being natives of rice-producing areas and the latter from areas producing other types of cereals. They are again sub-divided into four groups according to their type of work: group Ⅰ, very heavy work involving loading and carrying; groupⅡ, only a part of the work is heavy; group Ⅲ, light work; group Ⅳ, sedentary work.The survey is reported in two parts: Part Ⅰ deals with dietary investigations, Part Ⅱwith physical measurements and clinical findings.A detailed dietary investigation of 3-day duration is made of workers eating more or less steadily in two dining halls and only a general observation is made on the other four dining halls. The former is carried out by weighing the amount of food raw and after it is cooked and noting the number of portions divided into. Since the food is served more or less on the cafeteria style, it is necessary to ask the workers to keep a record of the specific dish or dishes chosen and the size and number of bowls of rice and/or the number of pieces of steamed bread consumed.The workers have three meals a day, the dietary pattern being more or less the same for all the meals. Vegetable oil is rationed and supplied in fairly adequate quantities. Both rice and bread are served as staple food and supplied in sufficient amounts. Since the mines are located in mountainous areas, the supply of fresh vegetables becomes a difficult problem, especially during the winter months. The daily menu tends to be somewhat monotonous.The calculated results show in general that the intake of calories may be considered as adequate. More than 80% of it is supplied by cereals principally in the form of rice or wheat.Protein is supplied chiefly by cereals and the quantity of protein ingested parallels closely with the calorie intake. It decreases from 80 grams or more per capita daily for the very heavy men workers (group Ⅰ) to 77 grams for the moderately heavy men workers (group II). The light workers (group III) consume still less protein, while the sedentary workers (group IV) are able to afford more meat and have a higher protein intake. The northerners tend to eat more wheat flour, so their protin intake calculated on the basis of percent of calories is higher.Calcium intake is found to be uniformly low for all the groups, more so for men than women, averaging less than 400 mg per person per day.The intake of iron may be considered as adequate.The amount of riboflavin averages only 0.50-0.70 mg per capita per day. Thiamine intake seems to be adequate. The adequacy of vitamin A supply is questionable, averaging 1,000-2,000 I.U., provided almost exclusively in the form of carotenes and in the winter time, vegetables are often stored for some time before use. The calculated vitamin C intake is probably much higher than the actual intake because the vegetables are not only stored but methods known to cause considerable loss of vitamin C are employed in the preparation of food.

In part Ⅱ, are presented the results of the physical measurements, which include standing height, body weight, shoulder width and grip strength, made on children of middle school and children's homes. Pelidisi index is calculated by using Pirquet's formula. In tables 1 to 6 are tabulated the average results of boys and girls of ages from 12 to 18 years old. Since the results of children's homes differ from those of the middle schools, they are tabulated separately. The differences in standing height and body weight of these two groups of children are shown in figures 1 and 2. The children from the Homes are considerably shorter and lighter than school children of the some age range. The boys tend also to be narrower in shoulder width.Compared with the physical measurements of the children of Shenyang in the northeast China, the Cantonese children are slightly taller and heavier at the beginning of this age range but the children of the Northeast grow at a slightly more rapid rate, so that at 18 years of age, they are about 2 cm taller, with approximately the same body weight.Hand grip measurements show that girls have only 2/3 the grip strength of boys. Values of Pelidisi are calculated for a]l the children. It is found that this index does not proper]y represent the nutritional status of the children of Canton. By all the other indices of the state of nutrition used in this survey, the school children are rated as having a higher nutritional status, than those of the children's home, while the Pelidisi ratcs them lower.Nutrition is considered to be one of the factors which causes differences in the growth and development of the various groups of children compared.

Thirty-six middle schools' boys, 14 to 19 years of age are selected as subjects. Most of them have been previously found to show symptoms associated with riboflavin deficiency. Their riboflavin intake is calculated to be about 0.4 mg per person per day.A one-hour urine sample is collected at S a. m. Immediately after collection, the boys are subjected to a 2 mg riboflavin loading test administered orally. Hourly urine samples' are collected for the four hours directly following the intake.The subjects are divided into 4 groups with 8 to 10 students in each group. Each student in group I is given orally a daily riboflavin supplement of 0.5 mg; group II, 1.0 mg; group III, 1.5 mg; and group IV receives no riboflavin supplement, but ointment treatment for scrotal dermatitis is applied. The procedure is carried out for a period of 14 days. The boys eat the ordinary school food and participate in the usual school activities.At the end of the 14-day period, a 1-hour urine sample is again collected. Another 2 mg loading test is performed, hourly urine samples being collected for 4 hours. All the urine samples are preserved with glacial acetic acid and toluene and stored in an electric refrigerator. The Lactobacillus casei method is used for the analysis of riboflavin.The results of the one-hour urine riboflavin analysis agree well with the dietary survey, showing very low values before the supplement, averaging 1.4 micrograms for the hour. After the administration of the supplement for two weeks, the riboflavin content in the one-hour urine samples increases stepwise with the increase in supplement, the highest being 11.4 for the 1.5 mg supplemented group. No increase is observed in the group IV using ointments.The 4-hourly urinary riboflavin excretion following the administration of the 2 mg load averages over per cent before the supplement and increases to 11.5, 15.6 and 17.8 per cent for the 0.5, 1.0 and 1.5 mg supplemented groups respectively. The curves in Fig. 1 show the hourly excretion of the 3 groups before and after supplementation.Clinical observations show that supplementation of 1 mg or more relieves some of the deficiency symptoms.It is suggested that in addition to the daily intake of about 0.4 mg 時iboflavin in the diet, 1.5 mg more should be added to keep the middle school boys in optimal riboflavin nutrition.

This study is undertaken simultaneously with the experiments for the determination of riboflavin requirement of middle school boys in Canton. The same subjects serve in both experiments. When the loading tests are performed, 2.0 mg of thiamine is given orally at the same time the riboflavin is administered. Supplements of 0.5, 1.0 and 1.5 mg thiamine are given at the same time and in the same order as the ribofiavin. The same urine samples are analyzed for thiamine as well as riboflavin. Thiamine is analyzed by the thiochrome method of Consolazio.The thiamine content in the one-hour urine samples of the subjects before the supplement averages 5.4 to 8.9 micrograms for the 4 groups. After supplementation, the thiamine content of the fasting samples of 1.0 and 1.5 mg supplement groups show definite increase, while the other two groups remain near the same levels.After the loading test, the 4-hour total excretion amounts to about 5 per cent of the 2 mg taken, with almost no difference among the groups. When the intake of thiamine has been supplemented for two weeks, the response to the loading test varies. The 0.5 mg supplemented group excreted 4.35% of 2 mg in 4 hours, while the 1.0 and the 1.5 mg groups excreted about 8%. The hourly excretions are shown in Fig. 1. The peak of excretion of the 1.5 mg supplemented group changes from the second to the first hour after the load test. The thiamine intake of these subjects is estimated to be about 1 mg daily. They are free from symptoms associated with thiamine deficiency and their 1-hour urine samples show that the quantity excreted may be within the range considered normal for healthy subjects, yet supplementation of 1.0 or 1.5 mg of thiamine is able to cause a greater and faster urinary excretion of thiamine. An additional intake of at least 1.0-1.5 mg thiamine to their ordinary dietary intake of about 1 mg may be desirable to ensure an optimum status of thiamine nutrition in the middle school boys.