Columbia University School of Dental and Oral Surgery - Dental Columbian Yearbook (New York, NY)

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YEAR BOOK tive colloidal changes. The best steels are made by the col- loidal process. An explanation for the degree of malleability of a metal is found in colloidal chemistry: the very small par- ticles of a metal have an air film which prevents their coming together. If, however. we heat the metal. the film is driven off and pressure of the two surfaces brings more points in contact. This also impresses the importance of clean sur- faces in soldering. In the manufacture of Argyrol finely divided or colloidal silver is used with Lysalbinic acid. which prevents Hoccula- tion. As much as 90 ,l, of silver can thus be dissolved. whereas in water alone, silver can only form a very dilute suspension. In boilers the lime salts in solution, like the bicarbonate, are decomposed by heat with the separation of calcium car- bonate. At first the salt is in the highly dispersed state, but soon becomes an amorphous, flocculated, crystalline, or com- pact colloid at the bottom, which process is called incrusta- tion or scaling. If now we add gelatin or glue to the tem- porary hard water, a permanent suspension is formed of the minute lime salt particlesg they do not flocculate, and can be easily blown off. Hitherto matter has been studied in bulk or in molecular solution. There is, however, a whole world of dimensions between, constituting the study of colloidal chemistry. This branch offers untold promises thru investigation. Every profession and every industry should direct its energies to the unraveling of the many secrets of nature which this science is ready to yield. To the dentist this field is very broad. The saliva is a typical colloid, and its actions should be studied ultra-microscopically. Digestion is a colloidal process. Some of the technical fields have already been mentioned. We have therefore to deal with a comparatively new science awaiting development, and it is barely possible to anticipate the wonder- ful discoveries to which this field may lead. A. BENNETT GOLDBURG. 555555 What is so rare as that day in June, When exams. are over, and pretty soon The faculty meets and casts your lot VVhether up the aisle you march or not. Things we seek and do not find:- Tlu-ee point contact-at the state board Things we find, but do not seek:- Exposed pulps and dams that leak. grind. 23 COLLOIDAL CHEMISTRY SOME DENTAL APPLICATIONS

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COLLOIDAL CHEMISTRY SOME DENTAL APPLICATIONS NINETEEN SIXTEEN precipitate. If now we pour the same amount of milk into another beaker, add some gelatin, and then add vinegar, we obtain no precipitate. These conditions exist in the stomach. The casein of the milk is very easily precipitated by the Hydrochloric Acid, causing digestive disturbance. This sub- stance is an irreversible colloid. Soap is an example of a reversible colloid. It crystallizes in an alcoholic solution and readily forms a colloidal solution when transferred to water. The adding of gelatin to milk prevents precipitation. Cow's milk has a comparatively large percentage of casein 131521 and a small percentage of albumin CIWWJ. Human milk has a greater percentage of albumin than casein, while the ass's milk has the least amount of casein. Hence the latter is the best milk to give when the former two have been found unsat- isfactory, as it has a large amount of protective colloid in the form of albumin and very little irreversible colloid in the form of casein. For the same reason iced cream containing gelatin is both more palatable and more digestible. Colloidal chemistry is of the highest importance in medical science as well as in biology. To quote Prof. Stewart W. Young of Stanford University: When one considers the relatively infrequent occurrence in biological systems of either crystalline substances or of substances that may readily be made to crystallize from water fthe universal biologic dis- persing mediumj, it immedately becomes evident that the chemistry and physics of such systems must be in the main colloidal. All bio-chemistry is thus in the main colloidal chemistry. To bring the above statement home more strik- ingly, it is but necessary to add that the formation of crystals between joints causes gout, while violent poisons such as cor- rosive sublimate, are transformed into irreversible colloids and form crystals in the cells. Hence we give albumin in mercurial poisoning to protect the poisonous solution and pre- vent its crystallization, a condition which permits of easy passage through the cell-membrane. Colloids do not diffuse or dialyse. Living cells show the Brownian movementg histology is properly a study of colloidal chemistry. Muscular movement likewise may be explained on the colloidal basis as was done by Prof. Janeway in the Acorn of April, 1915. All our foods and the entire composition of our body are mostly col- loidal. Some commercial applications are interesting from the dentist's point of view. India-rubber, for instance, in both the coagulation and vulcanization process undergoes distinc- 22

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NINETEEN SIXTEEN D 0 C. D. 0. S. ATHLETIC ACTIVITIES. N ,1914 our college was invited to participate T 'Ni In the Twentieth Annual Relay Race Carni- xm val of the University of Pennsylvania. We were represented by a quarter mile relay 743' team composed of Fisher '15 Miller '15, Reed '16 and Taylor '16. It was our first essay in the field of athletics and proved surprisingly encouraging, for we won third place against institutions of much larger student bodies. Each member of the team re- ceived a handsome silver cup. In the fall of the same year the class of 1917 developed a splendid basketball team which made a favorable showing against many well known institutions. The same class pro- duced an excellent baseball team. We sent another relay team to Philadelphia in 1915. Through the efforts of Prof. Carr and Dr. Sueskind an athletic association was organized and the team received official sup- port from the student body. Bryant '17, Norman '17, Reed '16, and Taylor '16 were our standard bearers. We gained 4th place from a field of 8 starters, the winning team breaking the record. This year the Pennsylvania race is again the chief event, and we are fitting out a team under most auspicious circum- stances. We still have with us last year's team, while Koth- loff, Rosenberg, Berglind, Kevitt and Overton form a fertile list from which to choose strengthening material. Taylor '16 was elected captain and Dr. Sueskind is again the faculty advisor. It is to be hoped that the student body will continue to support the athletic enterprises of the college and create with- in our institution a spirit akin to that existing in the big uni- versities, which will serve to bind more securely the friend- ships of the students and to stimulate at the same time en- thusiastic study, thus tending toward a realization of the Roman motto Mens Sana in Corpore Sanof' EDMUND H. TAYLOR '16. 555555 McCaffrey was reciting before Dr. Russel. Dr. R: What is White Vitriol? Mac: Zinc Sulphate. Dr. R: What is green Vitriol? Mac: A half of White Vitriol. ' 24