Most of the teaching on the absorption and metabolism of albumin is based on Ewald's work. Ewald's results are expressed in the form of a graphic chart, which, though at the first glance it appears very convincing, is in reality very complicated and difficult to follow. The data given do not seem sufficient to form a metabolic profit and loss account, and by recent work the results claimed seem to be quite exceptional. Plantenga found a very small absorption of albumin from the bowel even when salt was added, and Markwald came to the same conclusion. Plantenga in a second communication investigated the absorption of somatose from the lower bowel of a dog, and found an absorption averaging from 10 to 24 per cent. Edsall and Miller studied two patients very fully and found that the nitrogen absorption per diem equalled in the first case 3.04 grammes nitrogen or 19 grammes of protein, while in the second it equalled 3.8 grammes of nitrogen or 23.816 grammes of protein. There seems thus to be a concensus of opinion that albumen is but poorly absorbed even when predigested and when salt is added.

The writer in conjunction with Miss Robertson carried out a series of observations on six cases of gastric ulcer treated by rectal feeding, when a period of complete gastric rest seemed necessary as a therapeutic measure. In these cases the nutrient enema was carefully pancreatized before administration, and a complete analysis was made of the nutrient injections and of the urine and bowel contents. In every case the period of observation lasted over six days. On these observations the tables given are based. The figures in tables show the averages over the periods of observation expressed in grammes per cent.

Table I. Table To Show Protein And Nitrogen Of Food And Protein And Nitrogen Absorbed, With Caloric Value Of Absorption As Average Per Diem

Enema.

Absorption.1

Observations.

Protein.

Nitrogen.

Protein.

Nitrogen.

Caloric Value.

I. . .

7143

11.43

9.52

1.54

39

II. . .

4162

6.66

6.87

1.098

27

III. . .

49.06

7.85

10.52

1.7

43

IV. . .

46.75

7.48

3.86

0.618

15

V. . .

29.71

4.69

8.62

1.38

35

VI. . .

30.6

4.9

13.87

2.22

56

In observations 1 to 4 inclusive considerable amounts of protein were given (two eggs in each injection). In observations 5 and 6 the white of one egg was used along with milk. In all the observations the amount of protein absorbed is remarkably small. In observation 4, a poorly nourished and somewhat nervous subject, the amount absorbed is particularly small. In observations 5 and 6 where a smaller amount of protein was given in the injection, the absorption was just as good as when a larger amount was given ; in fact, in observation 6 the absorption of protein was better than in any of the preceding cases, and this notwithstanding the fact that milk was used in the enema. Milk is generally considered, except by Aldor, to be a food-stuff very poorly assimilated by the bowel in rectal feeding.

1 Caspari in a recent physiological study on Vegetarianism (Pfluger's Archiv, Bd. 109, 1905, s. 533) calculates that the amount of nitrogen contained in the digestive secretions equals 0.38 grammes per diem. If this observation be correct, and if it applies to cases under rectal feeding, it would increase the nitrogen absorption by that figure. The tables have not been calculated on this basis, as we have no sufficient evidence of the digestive secretions under rectal feeding.

Table II. To Show Absorption Of Nitrogen Per Kilo Of Body Weight

Observation.

N. absorbed.

Body Weight.

N. absorbed per Kilo.

I. . . .

1.54 grm.

515

0.029 grm.

II. . . .

109 „

465

0.0234 „

III. . . .

1.7 „

489

0.035 „

IV. . . .

0.61 „

50

0.012 „

V. . . .

1.38 „

45

003

VI. . . .

2.22 „

45

0.049 „

Average .

1.42 „

0.0297

When the absorption of nitrogen is considered as per kilo of body weight per diem, it is seen to be very small indeed. When one looks into the literature of the subject it is remarkable on what a small absorption of nitrogen, nitrogenous balance can be kept up in individuals who have become accustomed to a nitrogen-poor diet. Thus in six individuals on a nitrogen-poor diet observed by Hirschfeld, Kumagawa, Klemperer, Siven, and Albu, the average nitrogen absorption per kilo of body weight amounted to 0.116 grammes per diem, and these individuals were kept in nitrogenous balance. In Siven's own case indeed the intake of nitrogen was only 0.08 grammes per kilo of body weight, and nitrogen balance was kept up for a short time at least.

Table II shows the nitrogen absorption obtained per kilo of body weight. It averages 00297 grammes over the six cases, a figure far below even the minimum absorption, when nutrition balance was kept up in individuals used to a nitrogen-poor diet.

Table III shows the nitrogen balance in six cases of rectal feeding. In all it is seen to be markedly negative. The patients were losing nitrogen from the tissues.

Table III. Nitrogen Balance

Observation.

N. absorbed.

N. of Urine.

Balance.

I. . . .

1.54 grm.

3.27 grm.

- 1.73

II. . . .

1.098 „

5.5 „

- 4.408

III. . . .

17

2.4 „

-0.98

IV. . . .

0.61 „

6.31 „

-5.69

V. . . .

1.38 „

6.87 „

- 5.49

VI. . . .

2.22 „

8.12 „

- 5.89

10

From these observations it may be concluded that: -

1. Protein food, even when predigested and with salt added, is very poorly absorbed in rectal feeding.

2. The albumin of eggs, as generally used in rectal feeding, is a very expensive and unsatisfactory food-stuff.

3. There is no relation between the amount of protein injected and the amount absorbed. Absorption seems to depend more on the patient's individual capacity for absorption than on the amount of protein food given.