A considerable number of large samples of woman's milk which was supposed to be the cause of the poor condition of the infants taking it have recently been analyzed at the Hospital for Sick Children to determine vwNhether or niot there was an abnormally high or low concentration of one or more of the salt constituents. The fat and total nitrogen content were also estimated in the samples when sufficient milk was available. The fat content was frequently found to be lower than normal but the nitrogen content, though tending to be slightly lower than average, never ran beyond normal limits. While this work was in progress the question arose whether the nitrogen distribution into the casein, lactalbumin and globulin, and non-protein nitrogen fractions might not in some cases show unusual values. Accordingly a series of determinations was made, not only in as many of the supposedly abnormal milks as possible but in a large number of samples of milk from wet nurses supplying the infant wards.The nitrogen distribution commonly taken as normal is that ascribed to Schlossman as quoted by Rietschell with calcium hydroxide and the removal of excess calcium as oxalate. This method was used in order to remove sugar and fat as well as protein, in preparation for applying their methods for estimating urea, amino-acids, etc. So far as could be ascertained the non-protein nitrogen fraction of the other investigators is the nitrogen content of the filtrate after precipitation in the milk with phosphotungstic acid. In the work here reported tannic acid was used as the protein precipitant, according to the procedure of L. L. Van Slyke9. It is claimed that cystin and the three basic amino-acids, lysin,arginin and histidin, are precipitated by phosphotungstic acid, as shown by D. D. Van Slyke in his scheme for the hydrolysis of proteins 10. In a number of the milks analyzed in this study tannic acid and phosphotungstic acid were each employed as precipitant. In all these the nitrogen content of the tannic acid filtrate was greater than that of the phosphotungstic acid filtrate by 0 5 to 6 0 per cent. of total nitrogen, the average being about 2 per cent.METHOIDS EMPLOYED.-The complete procedure in this study was as follows:-20 c.cm. of milk was accurately measured into a 50 c.cm. volumetric flask and diluted with distilled water about 1 in 2, 2 c.cm. of 2 per cent. acetic acid were added slowly with shaking, and the stoppered flask was allowed to stand in the cold for twelve hours or more. After being made to volume, the contents were filtered through a dry high grade filter paper and samples were measured out for total nitrogen estimation according to the Kjeldahl-Gunning method. In most of the other milks not agreeing with the infants extreme abnormalities were found in the content of fat or of one or more of the salt constituents.Thus it is seen that with one possible exception this entire series can be taken as showing a normal range of values for the casein, the combined lactalbumin and globulin, and the non-protein nitrogen f...
No extended review of the literature on the chemistry of woman's milk will be attempted in this paper. The reader is referred for this to a r\l=e' \sum\l=e' \ by Nothmann1 in 1912 and another by Talbot2 in 1914. Quite large series of analyses have been made by many observers in which only a determination of the organic constituents and the total ash of milk was aimed at. Among the most important publications are those of Leeds,3 Meigs4 and Adriance5 in this country and those of Pfeiffer6 and Schlossman7 in Germany.The fat and protein content of woman's milk are now pretty definitely agreed on. The methods followed by many chemists in the sugar determination, as we shall see later, are open to criticism; and even in the total ash estimation, errors have been made owing to faulty methods.Considering how much work has been done on the chemistry of woman's milk, it is surprising that so few investigators have concerned themselves with the composition of the ash. With the exception of Harrington and Kinnicutt8 who analyzed a single large composite sample, almost nothing has been published in this country and very little abroad on this subject. It is true that both here and abroad isolated analyses have been reported, but they have been mainly in connection with metabolism experiments and have frequently been From the laboratories of the Babies' Hospital
In the course of some investigations at the Babies' Hospital on nutritional edema of infants, determinations of total solids of the blood and chlorid content of the plasma were made on a large number of children. Some interesting facts which were brought out in the course of this work are here presented. A discussion of the significance of the findings will not be attempted. Therefore, a review of the extensive literature on the osmotic pressure of the blood and the relation of blood water and salts to the fluids in the tissues, conditions which have been supposed to have some importance in the production of this form of edema, is hardly called for here.The literature of the two subjects which are considered in this communication is very limited. We have been unable to find reported any results of chlorid determinations in the plasma of infants' blood. Also, very few figures are obtainable on total solids of the blood, although the subject has been discussed by many pediatrists. Lederer1 deter¬ mined the blood water of suckling dogs. Lust2 has reported a number of observations on blood water of normal infants. His results will be referred to later. Gettler and Baker,3 at Bellevue Hospital, have carried out a very complete investigation of the blood of normal adults. The results given for total solids and chlorid in the plasma of adults are of especial interest for comparison with the figures obtained by us for normal infants.In all, seventy-nine determinations of blood solids and eighty-one of blood chlorid were made on sixty-seven different children. The ages ranged from 5 weeks to 6 years, but most of the subjects were under 2 years. Thirteen were well-nourished normal children from 2 months to 6 years of age ; some of them were breast fed, some were fed with modifications of cow's milk and some were on a mixed diet.The remainder were suffering from quite a wide variety of diseases, the principal groups being lobar pneumonia, bronchopneumonia, tetany,
In those cases in which it was possible to study the complete salt metabolism, a plan similar to that outlined in a previous paper 1 was followed. This, in brief, consisted of the careful determination of all sodium and chloride ingested and excreted during a three or four day period, following a preliminary period of three days on the same diet. Blood was withdrawn in the middle of the metabolism period. Complete balance experiments were not always possible, and in many such cases the daily excretion of chlorides and the effect of added sodium chloride on its excretion were studied. Such patients were always on "salt-free" diets consisting largely of milk at first, and later of vegetables, fruit, cereals and, later on, added protein. When figures for the intake are given in the latter cases, they represent approximate values only, obtained by computation of their amounts from tables of normal values and the measurement of the amounts ingested. Blood determinations were usually made when fasting, but in some cases this was impossible and little difference was noted when the venipuncture was nearer a meal time. METHODSBlood sodium was determined by the method of Kramer and Tisdall2 and the chlorides by that of Rappleye.3 Sodium in the food, feces and urine was determined by the standard gravimetric methods for estima¬ tion of potassium and sodium, cobalti nitrite being used instead of platinic chloride for the precipitation of potassium. The sodium values were obtained by deducting the potassium from the total. The urinary
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