University of the Pacific School of Dentistry - Chips Yearbook (San Francisco, CA)

Page 13 text:

OXIDATION OF TYROSINE. By G. P. Flores, Ph. D. fFrom the Physiological' Laboratories of the College of Physi- cians and Surgeons of San Francisco, Cal.J The tyrosine used in this Work was prepared from silk by hydrolysis with 20 per cent sulphuric acid. To 2 grams of tyro- sine suspended in 75 cc, of water, 600 cc. of a mixture contain- ing 19 grams of potassium hydrate C30 moleculesj and 17 grams of potassium permanganate. Vigorous oxidation began at once and the mixture was allowed to stand at room temperature for two days, as a small amount of the permanganate still remained unreduced. The solution was then heated for an hour in the water bathg ammonia, carbon dioxide, oxalic acid and volatile acids were determined by the ordinary methods. In this way I obtained from the above mentioned 2 grams of tyrosine, 0.185 of ammonia, 2.02 grams of carbon dioxide, 2.1 grams of oxalic acid, volatile acids equivalent to 16 cc. decinormal sodium hydrate. The volatile acids were found to consist of 0.03 grams of acetic acid, and some nitric acid, in the early part of the distilation a small amount of a white crystalline substance was driven over. This substance, which is probably para-oxybenzoic acid, was formed in such minute quantities that a positive identification was impossible. .The oxalic acid obtained was identified by its melting point, 990 C., rising after desiccation over sulphuric acid to 1890, and by the properties of its calcium salts. From these results it is apparent that in the oxidation of tyrosine by alkaline permanganate approximately four carbon atoms are utilized in the formation of carbon dioxide, while the remaining tive carbon atoms go to the production of oxalic, acetic, .and probably para-benzoic acids. The ease with which the benzene ring is broken would seem to point to the intermediate formation of quinone compounds with the tearing apart of the side chain and benzene ring. OH OH 2 +21-lad +2Clf3.cHNH2. Coon ffla on C HNH2. .gaou 20 +laQ'4-6.oo,42-f-4.6.2 . 18

Page 12 text:

STUDENT BODY. The Student Body is well organized, and is governed by a carefully prepared constitution, a copy of which is handsomely framed and hung in the main halway of the College. The objects of this organization are stated in the preamble of the constitution, to-wit: For the purpose of promoting a brotherly feeling, and of asserting our voice in matters pertaining to our Welfare, rights, and privileges, and securing unanimity of action, we hereby adopt and pledge ourselves to the following constitution. The organization meets on the iirst Wecliiesclay of each month, at 23 P. M., for the transaction of such business as comes within its scope. Officers for the ensuing year are elected on the first VVednes- day of the last month of the College term, all nominations having been made one week previous and the election being conducted according to a regular ballotine' s stem set forth in the constitu- tion. The active membership consists of all regularly registered students of the College who shall have signed the enrollment book of the organization. All members of the Alumni Association are honorary mem- bers of the Student Body. The officers for this year are: ei tw is y President ............ . . .VValter S. Royster Vice-President . . . .... James 1. Fleming Secretary ....... ...... F red H. Flynn Treasurer ........ .. .Roland E. Shirley Sergeant-at-Aims . . . .Henry C. Veatch 17

Page 14 text:

In order to obtain proof of this theory I have oxidized hydro- quinone by exactly the method used for tyrosine. Two' grams of hydroquinone suspended in 75 cc. of water were treated with 600 cc. of a mixture containing 32.2 grams of potassium permanganateg after standing for two days at room temperature decolorization of the permanganate was almost com- plete, the mixture was heated for half an hour in the water bath to obtain complete reduction. In this way I obtained 2.56 grams of oxalic acid, 2.52 grams of carbon dioxide and on dis- tilling after acidifying the solution a small amount of a white crystalline substance condensed in the receiver, which had the same properties as the substance obtained in a similar way on the oxidation of tyrosine, no volatile fatty acids could be detected in the distillate. THE STUDENT OF CHEMISTRY. H. Klein, Dept. of Chemistry. One of the greatest dangers the student of Chemistry should avoid is the accumulation of a large number of facts and com- mitting the mto memory. Perhaps, it should be added before proceeding further, that the above caution is chiefly intended for the beginners in the study. Usually, in a course of the sub- ject, such as is set forth in the I-Iigh Schools or Colleges, the mind is not allowed to dwell for any length of time upon any one thing, and so become thoroughly acquainted with it, but is hurried on and is soon bewildered in the effort to comprehend what has been discussed, what is presented and dreading what is yet to come. It is far better to dwell longer on a few subjects, provided these subjects are properly selected. A study, such as that of Chemistry, should not be swallowed piecemeal, rather masticated thoroughly and digested slowly and at leisure. The student generally learns a little about oxygen, a little about hydrogen, a little about nitrogen, etc., then a little about sodium, a little about calcium, etc., and particularly, when he comes across a Cto himj wonderful looking formul, immediately envelopes himself around it, and considers himself quite clever to be able to do so. In the study of Chemistry two mistakes are commonly made. The first is that of attempting to absorb the profoundest theories of the science before being prepared for them. They make but little impression upon the mind, and one only learns to repeat words about them, without having a true comprehension of their significance. It may be added here that one can readily observe how much more prepared is a student who has a knowledge of the subjects allied to Chemistry-Physics, for example, it being too obvious to mention how interdependent are the two subjects. The second mistake is that of allowing the lecturer or demon- 19