THE CHEMISTRY OF MILK. By JOSEPH H. KASTLE, Chief Division of Chemistry, and NORMAN ROBERTS, Assistant Surgeon, Public Health and Marine-Hospital Service. PREFACE. In the following pages the attempt has been made to present succinctly and yet sufficiently comprehensively for a thorough understanding of the subject what is known to-day regarding the chemistry of milk, and to give the results of the analyses of the Washington milk supply, made in the division of chemistry of the hygienic laboratory during a period of twelve weeks extending through July, August, and September, 1907. Part I of this communication deals with the chemical composition and general characteristics of milk. Part II deals with the chemical changes occurring in milk. Under this head are included changes in the composition of milk brought about, (1) by the action of heat and acids, (2) by the action of the enzymes of milk, (3) by the action of the digestive ferments, (4) by the action of bacteria and other micro-organisms, including the lactic acid fermentation and the abnormal fermentations of milk. Under this last section a few pages are also devoted to the subject of poisoning by milk, galactotoxismus. Under section 1 the destructive effect of heat on the milk enzymes is also considered. Part III is devoted to the consideration of legal standards governing the sale of milk in various localities. Part IV is devoted to the subject of milk adulteration, by skimming, watering, and the addition of foreign substances, including artificial coloring matters and milk preservatives. Some attention has been paid to the effect of artificial coloring matters and preservatives on the health of man. Part V is devoted to the general consideration of the Washington milk supply. Under this head will be found, (1) a brief outline of the methods employed in milk analysis, (2) the results of our analyses of the Washington milk supply, (3) conclusions regarding the general character of the Washington milk supply. In the preparation of this communication we have drawn freely from the writings of numerous authors on the subjects herein con |