all clinical purposes, is a perfect detector of pus, even better than the microscope, because those not familiar with it can see with the naked eye the bubbling produced by H,O, when brought into contact with pus. 2 2 In chronic cases, after the removal of the diseased bone surgically and the cleansing of the roots are effected, the pockets should be syringed with H,O,, to be followed by the injection of the xxiv. gr. solution of iodide of zinc in precisely the same manner as has been heretofore described. In very bad or almost hopeless cases, I use even a stronger solution, grs. xlviii. to the ounce; and when the gingival margins present a ragged border or cone-shaped slit, I apply the pure granular iodide to the edges of the slit once in three days, and soon find a perfect restoration of the normal festooning of the gingival margin. The injection into the pocket is to be repeated every fourth day. The length of time required for the cure of cases where two to four or five teeth are involved, varies from twelve days to four or five weeks, supposing the patient to be in ordinary good health. In those cases where constitutional treatment is required each must be met according to the indications, and the intelligent practitioner will decide for himself just what is needed during the period of local medication. The worst case that I have had during the past two years was where sixteen teeth were diseased, and it required constant care from March 26 to June 12, 1883. It was a case of three years' standing, and had been under the care of two gentlemen before it came to me, and the patient thought her gums were worse after leaving them than before treatment was commenced. Iodide of zinc has long been used by medical practitioners, in the form of a syrup for internal administration, and as an ointment externally for strumous inflammation and enlargements, chorea, etc. It is made by digesting four parts of iodine with a little more than one part of granulated zinc and twenty parts of water, until the liquid has become colorless. On evaporation it crystallizes and is ready for use. It is freely soluble in water. I present herewith a comparative table of the relative value of antiseptics and germdestroyers, which as all may see places iodine almost at the head of the list. This table is the result of a large number of experiments by M. Miguel, of the Observatoire de Montsouris, and shows the minimum quantity of the several antiseptics capable of preventing the development of germs and of adult bacteria in a liter of bouillon: utes. 4.50 Hyposulphite of soda Corrosive sublimate has the most powerful effect on bacteria; an aqueous solution of 1 in 20000 kills the spores of bacilli in ten minA solution of 1-5000 is thus a certain disinfectant, even when the time of exposure is very short. Koch finds that an aqueous solution of corrosive sublimate of 1-300000 puts a stop to the germination of bacterial spores. Sulphurous acid does not rank high as a disinfectant. Bacteria clinging to dry objects are killed after twenty to thirty minutes exposure to an atmosphere containing 1 volume per cent. of sulphurous acid. Spores of bacillus subtilis and bacillus anthracis are still capable of development after 96 hours exposure to an atmosphere of 5 to 6 vols. per cent. of sulphurous acid; even when moist they are very hard to kill with it. It is thus a very untrustworthy disinfectant, all the more so because it has little power of penetrating compact masses or bundles,-(Wolfhügel, Buchholtz, Schotte and Gärtner, Koch, Buchner). Carbolic acid in five per cent. solution will kill the spores of the anthrax bacillus in twentyfour hours. A three per cent. solution, however, will not do so in the same time. A solution of 1-400 checks the development of bacterial spores. Vapor of carbolic acid at ordinary temperatures is without effect; at 55° C. it kills the spores in two or three hours (Koch). Chloride of zinc in five per cent. solution has no effect on anthrax spores, even when they have lain in it for a month (Koch). Iodine, bromine, and chlorine are far more active than sulphurous acid. Bacilli cease to grow in the presence of iodine in the proportion of 1-5000, and of bromine 1-1500. Iodine water and chlorine water kill spores in one day; a five per cent. solution of chloride of lime in ten days. Benzoic acid, sodium benzoate, potassium chlorate, and quinine have little effect on spores. The following substances, even in dilute solution, have a restraining influence on bacterial development: allylic alcohol; oils of mustard, peppermint, turpentine, and cloves; thymol, chromic, picric, hydrochloric, and salicylic acids; quinine. The effect is perceptible in solutions of 1-300000 for oil of peppermint, of 1-800 for quinine, of 1-75000 for oil of turpentine. All disinfecting agents should be used in aqueous solution. In alcohol or oil they are either inactive or enfeebled. Bacillus spores still retain their power to germinate after lying for months in absolute alcohol. Pure oxygen is known to kill bacteria outright.-Page 75, 275-8, Zeigler. This system of treatment, based on the primary injection of H2O, into the pockets as a ready method of cleansing them and at the same time furnishing nascent oxygen to destroy the unclassified micro-organisms there present, and the subsequent injection of the zinc iodide, for its well-known stimulating and protective effects on the reparative material exuded, which is always ready for organization after being thus carefully protected, renders it almost certain that if careless probing or syringing of the pockets is prohibited, and the mouth is well cleansed with an antiseptic wash, a reproduction of lost tissues may be confidently anticipated. In conclusion, permit me to say that this remedy, when used faithfully in conjunction with peroxide of hydrogen, the most valuable germ-destroyer known up to the present time, arms us so well that I believe with expert handling of the probe to discover the concealed pocket, skillful removal of all deposits and edges of diseased bone, conjoined to an exact knowledge of constitutional needs, that we no longer need feel dismayed when brought face to face with a genuine case of pyorrhea alveolaris. DISCUSSION ON DR. FRIEDRICHS' PAPER. Dr. ATKINSON: The discussion of this subject reaches to the foundation of the change of nutrient activity from health to a diseased form, and involves all the differences of the syphilists and the antisyphilists from the earliest time of pathological discussion. It is very clear that the paper and nearly all the references in it are of the mass character that reach at presentments that are competent to be observed by the unassisted natural vision, from which we cannot explain any of the changes that take place, nor settle the difference between the appearance of a tissue that is under what is here called cachexy or syphilis, forgetting entirely that there may be a syphilitic cachexy. If you will look closely into some of the statements of the paper, you will see that they are gratuitous. It is said that the syphilitic virus holds its court in the embryo. If it holds its court in the embryo, this paper may be true when it says, "There is no distinctive characteristic in the temporary teeth." I think the writer really comprehended what he said, but did not say what he meant,-that there was no syphilitic characteristic manifest so far as his observation had gone in the temporary teeth; but that there are characteristics in the temporary set is absolutely known, and by them we are enabled to distinguish the temporary from the permanent set, and if we wish to see these differences and discuss them, we at once go outside of the range of mass observation and must be acquainted with the histology of the tissues to be masters of the subject. The entire mass view tells us at once that we are only beginning to comprehend what function is, for the very reason that because there is such a great variety of molecular changes that enter into the constitutions of different individuals the standard of health is not a unit. The standard of health is different for every individual and we can only generalize upon those questions if we deal with them in a mass way. Until we know the molecular changes whereby the food is converted into the tissues that constitute the organs of the body, we will simply be striking in the dark and unable to satisfy our own minds of the ratiocinative process through which we go in the examination of particular cases in order to arrive at what we call a diagnosis; and probably the greatest obstacle in the way of our proper advancement is, that we have not been willing to be rigid in scrutinizing our own mental processes, so as to know when we are satisfied with our examination and with the judgments that we pronounce, so that we could religiously say that we did know what we were about. Dr. PEIRCE: The paper just read, it seems to me, has dealt with the facts as we have them presented to us by physicians and by the literature of the day. It is mass observation, it is true, but from mass observation we can learn a great deal. It is well known to the dental profession that certain character. istic impressions prominent upon the permanent teeth are designated by the medical fraternity as syphilitic markings. This we have heard affirmed from the time we entered the profession whenever these peculiar abnormal conditions were a subject of conversation with a member of the medical fraternity. From observation dentists have been taught that other conditions will produce these same appearances and therefore it is unjust to attribute them always to the one specific disease. For that reason I was rejoiced in listening to the paper. I felt that it had taken up the subject and presented it in an intelligent manner to this body. Observing practitioners recognize the fact that a child who has suffered for the first six months of its life, or during the period of the eruption of the deciduous teeth, with what is termed interrupted dentition, going through a series of convulsions with every tooth erupted,―must have the permanent teeth very badly developed. It may have markings on the permanent teeth to correspond with those that have been termed syphilitic. If a child is placed in my chair with the permanent teeth erupted and pitted, I can say to the mother, "This child had some severe illness during such or such a period of its infancy." If the child was ill from birth all through the first year or especially from the fifth month up to the end of the first year, you will find the central incisors and the first permanent molars are imperfectly calcified, with lines or pits over the masticating surfaces of the molars and across the labial surfaces of the incisors. You will probably find the inferior incisors broad at the cutting edge and constricted towards the neck, and you will usually find the markings prominent which are laid down by Hutchinson as belonging to syphilitic teeth. I have, I think I can safely say, twenty patients in my practice who have just those conditions of the teeth that Hutchinson portrays in his diagrams as being due to syphilitic taint, but I am satis. fied that if there was any syphilitic influence in these cases, it dated back several generations. Whenever we have an abnormal condition during the calcification of the permanent teeth that is sufficient to interfere with nutrition, we have the permanent teeth deficient in the quality and quantity of enamel and dentine. This is all, as Dr. Atkinson has said, mass observation. If we go closer to the histology of the teeth we shall find imperfect calcification throughout the whole tooth, provided mal-nutrition lasted during that period. If a child has had no ill health until the end of the first or some time during the second year, and then is attacked with scarlet fever and is ill for six weeks, you will find the permanent incisors and |