Page:Popular Science Monthly Volume 20.djvu/734

714 him that imparting the power "of repeating classifications of animals with all the appropriate definitions" had nothing to do with communicating genuine knowledge. He prepared a series of laboratory notes sufficient for the dissection of a few plants and animals, and used Huxley and Martin's text-book, after it was published, as a laboratory guide. The school board provided eight Beck's students' microscopes, and, he says, "we begin with the study of the torula; we then take in succession the following organisms: protococcus, amœba, bacteria, mold, stone-work, ferns, flowering plants, infusorian fresh-water polyp, clam, lobster, and frog. We devote to laboratory one hour daily for seven months. At the end of the course come morphological and physiological generalizations. Our classes number about eighty, and are divided into working sections of sixteen each. The average age of the students is sixteen years, rather more than half of them being girls. I have found the students eager and enthusiastic, and the large majority of them regret the untimely end of their study of biology," which is limited by the procrustean regulations of the school-course.

Nature of Diphtheria-Poison.—Drs. H. C. Wood and Henry Formad, co-operating with the National Board of Health, have been studying the nature of the diphtheritic contagium. They began with inoculating rabbits, under the skin or in muscles, with diphtheritic membranes taken from the throats of patients in Philadelphia. Not diphtheria but tuberculosis followed as an indirect and not a direct result of the inoculation, the relations between the two diseases seeming to be only apparent. When the false membrane was inserted into the tracheas of the rabbits, severe trachitis was produced, with an abundant formation of false membrane, identical with that of diphtheria. It was shown by further experiments that the production of false membrane involves nothing specific, but that any trachitis of sufficient severity is accompanied by it. The product differs from that of true diphtheria only in its containing fewer micrococci. Diphtheritic poison was next obtained from Ludington, Michigan, where a severe epidemic was raging. Inoculations with this matter, whether made under the skin, in the muscles, or in the trachea, were all followed by similar results, namely, a quick affection, a rapid spread of the local symptoms, and death; and the blood, examined during life or after death, was found to contain micrococci precisely similar to those found in the Ludington cases; and in a few instances the plants were found in the internal organs and the bone-marrow. The urine of patients suffering from malignant diphtheria is full of micrococci, and is even more deadly in its effects than the membrane. When cultivated, micrococci from Ludington grew rapidly up to the tenth generation, and those from Philadelphia ceased their growth in the fourth or fifth generation, while those taken from a furred tongue, which showed similar shapes, never got beyond the third transplantation. The conclusion was drawn that the micrococci found in ordinary sore-throat and those of diphtheria differ only in their reproductive activity. When rabbits were inoculated with cultivated micrococci, diphtheria was produced with the second generation, but never with any later product. Diphtheria may be self-generated whenever conditions arise within the body or act upon it from without competent to stimulate the inert micrococci in the mouth into active ones.

Scientific and Popular Experiments in Pathology.—Mr. John Simon, D. C. L., LL. D., in his address before a section of the International Medical Association, on "State Medicine," has forcibly presented the duty of the state to facilitate and encourage scientific researches into the causes of disease. All that we know or can know on this subject, he maintains, is and must be learned by experiment. The experiments that give us the teaching we seek are of two kinds: scientific experiments, carefully prearranged and comparatively few, performed in pathological laboratories, and for the most part on other animals than man; and "the experiments which accident does for us, and, above all, the incalculably large amount of crude experiment which is popularly done by man on man under our present ordinary conditions of social life." Thus, in regard to Asiatic cholera, we have the scientific infection experiments of Professor Thiersch