Fever, Yellow, by Theod. Walzer,...... Flint, Austin, on Physical Exploration and Diagnosis,. Forceps versus Embryulcia, Fox, G. M. on Injury to Perinium,....... Fracture, Compound, of the Thigh, by D. Prince,. Fractures, Ununited,..... Freer, J. W. on Fractures, &c........... Freese, J. R. on Forceps versus Embryulcia,.. Goodbrake, C. on Pre-Expulsion of Placenta,.. Hall, W. G. on Neuro-Pathology of Fever,........ Heart, Movements of, Indicated by a New Instrument,. Hernia, Inguinal, with Operation by D. Brainard,.. Hoblyn, Richard D., Dictionary of Terms, &c.............................. ................................... Illinois State Medical Society, Transactions of,........ Infants and Children, Diseases of, by Fleetwood Churchill, Injuries of Shoulder Joint, Diagnosis of,... Intermittent Insanity, Case of Introduction to Practical Pharmacy, by Edward Parrish,.. 334 .318, 181, Professional Changes,..... .336 Professional Reputation, 533 Prince, David, Case of Compound Fracture of the Thigh,. .125 ............. Pustular Eruption of the Skin, from the Internal Use of Tartar Emetic,.....101 Ranking's Half Yearly Abstract,. .134 Regurgitation, Obstinate, Treated by Chloroform, by Isaac E. Taylor,......551 ..497 Rush Medical College,. .573, 479, 480 Scarlatina, Treatment of by Oil of Turpentine,.. .148 .75 Sherman, N. on Cancer of Penis,.... 422 Simpson, James Y. Obstetric Memoirs and Contributions of,......................... Taylor, Isaac E. Case of Obstinate Regurgitation Treated by Chloroform, 551 Tetanus, Therapeutics and Pharmacology, by George B. Wood,.. Thompson, Allan, on Origin of Entozoa,..... .............509 ... 521 Watson, John, on the Medical Profession of Ancient Times,... .433 Willard, E. R. on Turning with Rigid Os-Uteri,.................... .423 Wood, George B. on Therapeutics and Pharmacology, .567 Woodward, Benjamin, on Cases in Practice,.......................... 59 ARTICLE I.-Report of the Committee on the Means of Preserving Milk, and on the Influence of Pregnancy and Menstruation on the Composition and Nutritive Qualities of that Fluid. Prepared for the American Medical Association, Annual Session of May, 1855. By N. S. DAVIS, M.D., &c. From the Transactions of the American Medical Association. THE general subject assigned to your Committee requires consideration under three distinct heads, viz: First, the means capable of preserving milk free from injurious changes in its composition for an indefinite length of time; Second, the changes which the milk of the female undergoes during the period of menstruation; and, Third, the changes which occur in the same fluid in those cases where pregnancy supervenes while lactation is still going on. If we keep in mind the whole period of human life, from the tender period of infancy to old age, we shall readily perceive that Milk is not only one of the most important, but also one of the most essential articles of diet in the possession of man. It is the only article provided by nature for the first period of life, and for which the genius of man has never succeeded in devising a substitute. Embracing in its composition all the elements necessary for the nutrition of the various structures of the body, and in a form so bland and easily absorbed as to be adapted to the most delicate condition of the digestive apparatus, it is often no less valuable to the invalid and the convalescent than to the infant. In this one fluid we have, in the form of organic matter, casein, oils, and sugar; and as inorganic matter, phosphates of lime, magnesia, and iron, chlorides of sodium, potassium, and soda; and sulphur. All these ingredients are either dissolved or suspended in water, in nearly the following proportion, viz: The only ingredient not in a state of complete solution is the oil or butter, which exists in the form of minute globules, lighter than the water, and consequently disposed to rise to the surface whenever the milk is allowed to remain at rest. The casein, which is one of the most abundant ingredients, closely resembles albumen in its chemical composition, and like it, liable to undergo decomposition or change by exposure to heat or air in a moist state. But of all the constituents of milk, the sugar is the quickest to undergo changes by time and temperature. Chemically identical with grape sugar, it is very easily converted into lactic acid by a process of fermentation. At an ordinary summer temperature, from six to twelve hours is sufficient to effect the change, or at least to begin it. In the natural condition of fresh milk, the soda is in combination with the casein, and is the means of rendering the latter soluble in the water. No sooner, however, is lactic acid generated from the decomposition of the sugar, than it unites with the soda, leaving the casein free, and consequently insoluble, and in the form of white coagulated masses. These changes constitute the process, familiarly known as the "souring" of milk. By this very brief glance at the composition of milk, we see in the number and nature of its ingredients, and the feeble affinity by |