Much of our knowledge of the absorption of fat is based on the work of Munk and Rosenstein. Their observations were made on a patient with a lymph fistula through which the absorbed chyle could be collected. The patient was kept on a fat-poor diet, and then given enemata of an emulsion of 15 grammes of lipanin, in 0.4 per cent saline solution. The lymph showed a rise in fat contents of from 0.18 to 0.45, that is to say, 3.7 per cent of the oil was absorbed. In the second observation the fatty content of the hunger-lymph was estimated, a cleansing injection was then given followed by an enema of 20 grammes of lipanin in soda solution. The lymph showed a rise in fat from 006 to 0.37 per cent, and after 9 hours was still 0.23 per cent. There was absorption therefore of 5 1/2 per cent of the fat of the enema. Robert and Koch found that emulsified fat was slowly absorbed in small quantities, while unemulsified fat was but little absorbed. Munk and also Armschink found that the lower the melting point of the fat the better it is absorbed. Deucher concludes that 10 grammes of fat per diem are absorbed with difficulty even in favourable circumstances, and that the best results are got by the use of small quantities retained in the colon a long time, and with salt added to the injection.

Table IV. Table To Show Absorption Of Fats As Average Per Diem

Observation.

Fat of Enema in Grm.

Fat absorbed in Grm.

Percentage of Absorption.

Calorio

Value.

I. . .

103.37

4585

44

426

II. . .

4744

2387

51

222

III. . .

40.24

1446

35

134

IV. . .

39.61

5.45

12

50

V. . .

918

-2.55

-

-23.71

VI. . .

14.35

3.47

24

32

In these observations the fats were estimated by weight after extraction with ether, so that the resulting figures may be more correctly termed ether soluble bodies. The results obtained differ materially from those of Deucher. They show a definite relation between the amount of fat given and the amount absorbed. The maximum of absorption, 45 grammes in observation 1, was where the maximum 103 grammes were given in 24 hours. Considerable fat absorption was got whenever a large amount of fat was used in the enema. In observation 4 a small amount was absorbed, namely, 5.45 grammes, equal to 13 per cent., as compared with observation 3, where, with practically the same amount, in the enema, a considerably larger quantity was absorbed. It is to be noted that the patient in observation 4 was poorly nourished and exceedingly emotional and that albumin was equally badly absorbed. Observation 5 is difficult to explain; the amount of fat recovered from the stool was greater than the amount injected by an average of 25 grammes per diem. The patient was a very well-nourished but somewhat chlorotic young woman. One can only conclude either that her fat absorption was practically nil and that the surplus amount recovered was accounted for by the digestive secretions, or that some unauthorized article of food was taken by the mouth. The latter explanation was indignantly denied by the patient, and considered impossible by the nurses in charge, and is not borne out by the figures of the nitrogen and sugar metabolism.

Table V. Table To Show Loss Of Nitrogen Of Tissues And Loss Of Weight In Relation To Fat And Sugar Absorption As Average Per Diem By The Patient

Observation.

Nitrogen of Tissues.

Loss in Weight in Kilos.

Fat absorbed.

Sugar absorbed.

Caloric Value of Absorption

I. .

1.73

0.378

45.85

438

606

II. .

44

0245

2387

38

378

III. .

0.98

0.405

1446

61.85

388

IV.

569

0.518

5.45

50.61

258

V.

549

0.583

-2.55

811

308

VI.

589

0.778

347

3696

184

In glancing at Table V it is interesting to note that fat absorption seems to play an important role as a nitrogen-saver. The loss of tissue nitrogen for the six observations is very much larger in those where the fat absorption is poor. Taken as a whole the figures show that emulsified fat is a very useful ingredient in rectal enemata, and is very much better absorbed than is generally considered.