But organs, like individuals, do not rise to the full performance of their duties unless called upon by the necessity for their activity; and, as I pointed out in 1866 ("On Tuberculosis," p. 40, second edition), "As the mother is deprived of fat-elements by lactation, so is the child deprived of them by a persistence in a diet deficient in milk. In the case of the child thus deprived of fat, a double injury is done, first, by cutting off the supply of fat-elements necessary for the protection of the tissues; and secondly, by paralysing the function of the pancreas by prolonged inactivity." I venture to think that this is a point deserving far more attention than it has yet received. It accounts in a great measure for the impossibility of restoring these ill-nourished, wasted children by any kind of natural diet after they have been allowed to remain in a chronic state of defective nutrition. A child that has been long fed upon diet deficient in fat fails to develop the fat-digesting properties of the pancreatic secretion, and thus, when proper food is at last presented, cannot make use of it for nutrition. (See pp. 272-4, "On Loss of Weight, Blood-Spitting, etc." 2nd Edition.)

It is probable, therefore, that it is due to this conjunction of circumstances that these wretched cases of fatal infantile wasting occur: the food deficient in fat not only fails to nourish the child, but fails to develop the function of the pancreas for the digestion of fat at a later period of life; the craving of the child due to the deficiency of assimilated fat is met by starchy food, which it has not the power to digest, and which, if digested, cannot supply the place of fat. Thus it is literally starved from first to last of those elements of nutrition especially essential in early life. We cannot, therefore, be surprised that such cases have proved obstinately fatal, neither is it anything but what one might expect, a priori, that they get rapidly well when Pancreatic Emulsion of fat is added to their diet, for by this means they are enabled to assimilate both fat and starch.

Certainly of all the satisfactory remedial effects of Pancreatic Emulsion, none equal the almost magical recoveries of some of these miserable wasted children. The cases in which I have seen it administered within the last eight years are too numerous to relate, and I will only briefly mention three of those which first especially excited my attention.

1. A poor woman came to the Royal Hospital for

Diseases of the Chest with a child presenting the most exaggerated features of emaciation of every part, except the abdomen which was large and hard. She was very excited at having succeeded in gaining admission, and explained in great haste that "all she wanted was some Pancreatic Emulsion, which she had learned could be obtained at the Royal Hospital." She said the child had been even worse than I saw it, that everybody told her it was a hopeless case, and that she had carried it to her mother's home in the West of England, where it appeared to be slowly dying, when a charitable visitor came in and gave her a bottle of Emulsion, saying that he had seen just such a case cured by it. She gave the emulsion, and the child began to improve so wonderfully that she was able to bring it back to London, where it continued to mend till her bottle of emulsion was finished, when it rapidly fell back, and became nearly as bad as ever, before she could find out where to procure more of the remedy. This she had just done, and hurried off to the Hospital. The child had diarrhoea; but she said she knew that would stop if I gave her emulsion, as it had done so before. I did as she asked - let her have as much emulsion as she wished, and the child got absolutely well. I have seen it this year (1875) a well-grown, plump, hearty little girl. The woman has since had two other children, each of whom has in turns shown signs of marasmus like its elder sister; in one, when brought to me, the lungs presented small crepitation from end to end; but both of these children were put upon emulsion at an early stage of their wasting, and made easy recoveries.

2. Soon after these cases occurred, Dr. Dingley, of Argyll Square, consulted me about a little patient of his in Soho, who was wasting in the same way; and as all the usual remedies, both in medicine and diet, including cod liver oil, had quite failed to arrest the downward progress of the case, we agreed to try the Pancreatic Emulsion. I did not see the case again, but Dr. Dingley has since informed me that from the time of commencing the Emulsion the child began to improve, and steadily progressed till it got perfectly well; and it remains well to the present day (1875). Dr. Dingley was so impressed with the success of the remedy in this apparently hopeless case, that he tells me he has since resorted to the same treatment in all similar cases with equally satisfactory results.

3. At the Oxford meeting of the British Medical Association, Dr. Langdon Down told me of a case that had made a great impression upon him, and it is especially important as coming from a man of his large and intimate experience in all that relates to the affections of childhood. The following note from Dr. Down graphically indicates the outline of the case: -

The patient at Reigate was seen by me in consultation with Mr. Steele, in the spring of 1867. She was in the most attenuated condition I ever remember seeing. It appeared to be the extreme marasmus of mesenteric disease. The lungs were healthy. The treatment had been most judicious and exhaustive. As something which had not been tried, I suggested the Pancreatic Emulsion. The improvement was coincident with the altered treatment, and was very progressive. Five months after I was asked to see her by her father, to test whether I could recognise her. She was playing croquet, and I could hardly believe that the one pointed out to me was our patient, the change was so great. She has ever since had excellent health."

These cases, which are well known to many persons besides myself, may appear somewhat "sensational," but they are only samples of numerous others which hâve occurred in my own practice. The fact is, that when these cases are properly selected for the treatment, they are all "sensational;" for the rapidity with which it takes effect, and the completeness of the restoration to health of children who appeared to be hopelessly dying, is simply startling.

I have proved over and over again that, whether in children or adults, no amount of milk or cream, however good, will do instead of Pancreatic Emulsion, and I have tried to discover why this should be. Milk, so far as this part of its composition is concerned, is simply an emulsion of fat; and Pancreatic Emulsion, as I have shown in the paper to the Royal Society already referred to, is not, as formerly supposed, a chemical combination, but a true emulsion. Why, then, does not milk answer as well? I believe the explanation to be very simple, and that it turns upon the following points: -

(a.) The fineness of the particles of fat in the Emulsion, and the absence of albuminous envelope.

(b.) The permanent character of the molecular mixture of fat and water.

(c.) The proportion of fats having high melting points. (See "On the Importance of Distinguishing between Solid and Liquid Fats")

(a.) In my first paper on Pancreatic Emulsion ("Lancet," September 10, 1864), I gave the measurements (made by the late Mr. Farrants, President of the Microscopical Society) of the particles of fat in cod oil and beef-fat emulsions, as then prepared for me; showing that the majority of the particles in the cod-oil emulsion ranged from the 16,000th to the 1,200th of an inch in diameter, and those in the beef-fat emulsion from the 10,000th to the 2,500th of an inch; and, according to Bowman (" Practical Handbook of Medical Chemistry," p. 174), " The size of the globules in healthy milk varies from a mere point to about the 2,000th of an inch."

Since I published Mr. Farrants' measurements, Pancreatic Emulsion has been made by a much more equal and satisfactory process than at that time, and I have just (1875) examined a chance specimen procured from Messrs. Savory and Moore, in which the large majority of the particles of fat range from the 21,600th to the 14,400th of an inch in diameter, the prevailing size being the 18,000th of an inch; while in a specimen of good new milk (cold), which I have also just examined, the large majority of the particles of fat range from the 7,200th to the 3,600th of an inch in diameter, the smallest being the 10,800th.

(b.) The permanent character of the Pancreatic Emulsion is very remarkable, far exceeding that of milk. It "differs entirely from all other kinds of emulsion of fatty matter, whether chemical or mechanical. All other emulsions of fat are destroyed by ether, the fat being restored at once to its original condition. The influence exerted by the pancreas upon fats, therefore, appears to operate by breaking up the aggregation of the crystals of the fat. It alters the molecular condition of the fat, mingling it with water in such a way, than even ether cannot separate the fat from the water. A permanent emulsion is thus formed, ready to mix with a larger quantity of water whenever it may be added." ("Proceedings of the Royal Society," already referred to.)

(c.) In the "Chemical News," September 4, 1868, I stated my reasons for believing in the importance of fats of high melting points, such as stearin, margarin, and palmitin, over those of low melting points, such as olein, as elements of food and medicine; although further experiments and investigations are still needed on this interesting subject. (See p. 127.)

Pancreatic Emulsion of solid fat, consisting principally of stearin, margarin, and palmitin, is therefore quite a different thing from milk, the fat of which is principally olein.

Now, the nearest approach to a pancreatic emulsion is what may be called, nascent milk, by which I mean milk just secreted - milk that flows from the mammary gland as it is formed, or as mothers term it, "as the draught comes in." In this the emulsification is finest and most perfect, but every minute that elapses after the milk- is secreted, deteriorates this perfection of emulsification, until, as we know, whether retained in the lactiferous ducts or in an artificial vessel, but especially in the latter, and when allowed to cool, the cream separates from the water of the milk, never again to be susceptible of the same emulsification with water in which it first existed, except under the influence of pancreatic juice.

I submit that this is the secret of the superiority of lactation, and especially of lactation at the time "the draught comes in," over every other kind of infant-feeding, whether in man or in the lower animals. It forms an important distinction between milk-diet supplied by the natural process of suckling, and milk-diet administered artificially, and affords some reasonable colour to the old-standing belief in the efficacy of "new milk warm from the cow" for delicate children, and to the remarkable recoveries recorded in ancient times of old persons nourished by lactation when everything else had failed.