(C.) - From the proceedings of the Royal Society, No, 97, 1868.

On the Special Action of the Pancreas on Fat and Starch. By Horace Dobell, M.D., etc.

I have been engaged for several years in experimenting with the secretion of the pancreas. The enquiry of which I now make known the results has reference especially to the mode of action of the pancreas upon fats - a point which has been the subject of investigation by various physiologists ever since the discovery of the influence of the pancreatic fluid on the absorption of fat by Claude Bernard, nearly twenty years ago.

In the chemical parts of my experiments, I owe much to the efficient aid of my friend Mr. Julius Schweitzer, and to the energy and perseverance with which he carried out my suggestions under many difficulties.

The objects of my investigations have been as follows: -

1. To discover the exact character and nature of the influence exerted by the pancreas upon fats.

2. To discover a means of obtaining and preserving the active principles of the pancreas in a form suitable for experi ment in the laboratory, and for administration as a remedial agent.

3. To discover the effects of the administration of the active principles of the pancreas as a remedial agent in certain wasting diseases, and to test, by an experimentum cruris, the truth of a conclusion on this subject, at which I had previously arrived by a process of inductive research.

I shall not occupy the valuable time of the Society by narrating the many more or less unsuccessful experiments, but restrict myself to a concise record of those attended with success.

Experiments were made with the pancreas of several different animals, but that of the pig was selected for the experiments of which I am about to give the results, as being nearest in the character of its functions to that of the human subject.

In order to ascertain the normal reaction of the pancreatic juice, and whether this is altered by the length of time that has elapsed since the last meal, the following experiment was made with the assistance of Mr. Schweitzer and of Mr. Harris of Calne, who kindly placed his extensive pig-killing establishment at our service for the purpose.

On March 22, 1866, forty pigs were killed, and the pancreas of each examined immediately after death; the killing and examination were so rapidly conducted, that the pancreas was in each case examined while warm from the body; and the killing and examination of the forty pigs in succession occupied less than an hour.

The pigs were killed ten at a time. The first ten had been fed two hours before they were killed, the second ten live hours, the third ten nine hours, and the fourth ten had not been fed for two days.

The pancreas in each group presented the same characters in size, colour, and reaction. Each pancreas was cut through so as to lay open the principal duct, but in no case was there any fluid in the duct. Litmus-paper was applied to the interior of the duct and to the divided gland-cells, and on being pressed sufficiently against the tissues to absorb moisture, the paper was in each case reddened where it was moistened. This acid reaction was not found in the fat and muscles of the animal.

At my request, Dr. Collins examined the reaction of the pancreas in a series of cases at the moment when all the digestive organs were under active excitement. He gave the pigs a good and relishing meal, and while they were eating it, divided the spinal marrow in the neck, so as to destroy sensation in the body. The pigs were immediately cut open, the pancreas removed, and its reaction examined. On August 3rd he wrote me, 'As you requested, I have tried a series of experiments upon the pancreas, parotid, and sublingual glands. The two latter have a decidedly acid reaction, but the pancreas I am not quite so certain about; in one batch of pigs killed in Buckinghamshire it was alkaline, but in another lot in Hertfordshire it was acid.'

The reaction of the pancreas is always acid when it reaches the laboratory for experiment as quickly as possible after removal from the animal. This we have proved in many hundreds of instances.

To discover the influence of the pancreas upon fat, the fresh pancreas of the pig, freed from all adhering blood and other extraneous matters, was cut into small pieces, bruised, and mixed with lard; and to this mixture water was gradually added. In the bruised condition the pancreas had an acid reaction. By stirring this mixture of pancreas, lard, and water, the fatty character disappeared, a thick, white, creamy fluid being formed, which, on standing, solidified into a firm pasty mass. This mass had also an acid reaction. In order to free it from the débris of, pancreas, it was pressed through muslin, and a uniform smooth creamy emulsion remained. This emulsion rapidly putrefied, but remained a permanent emulsion until putrefaction set in.

The following are the microscopical characters presented by pure lard before mixture with pancreas, and by this emulsion, which I call 'crude emulsion': -

1. 'Lard' (pure). - Aggregations of ordinary acicular crystals of margarine. No oil-globules. No water.

2. 'Crude emulsion.' - A tolerably uniform granular mass with separate acicular crystals of margarine, oil-globules, and water abundantly distributed throughout the mass. In some places the crystals are aggregated as in No. 1. The granules range from the 1/3000 to 1/15000 diameter.

This mixture of fat and water differs from all other mix-lures or chemical combinations of fat and water in the following particulars: -

When the 'crude emulsion' is put into ether, the ether separates it into two strata - a. An ethereal stratum above, containing the fat.

b. A watery stratum below.

When the upper stratum (a) (ethereal solution of fat) is drawn off and the ether evaporated by a cautiously regulated heat, a pure crystalline fat remains which I call 'pancreatized fat.' This pancreatized fat has no tendency to putrefy, and will keep for an indefinite period. It presents the following characters under the microscope: -