I9I5] Edgar G. Miller, Jr. 221 



was " worn very little or not at all," or which was " considerably 

 worn without exposure of dentin." 



Unfilled teeth, with sound enamel that was (a) " considerably 

 worn without exposure of dentin," (b) "worn very little or not at 

 all," or (c) "worn through and exposing dentin," when subjected 

 to two daily brushings, in comparative tests, f or 8 months, with ( i ) 

 dilute vinegar (i : i), a (2) common tooth powder or a (3) com- 

 mon tooth paste, with intervening salivation, were uninjured. No 

 change of any kind could be detected as a result of the vinegar treat- 



ment. 



Two daily brushings of teeth similar to those referred to in the 

 preceding paragraph (some of them filled), with dilute vinegar 

 (1:1), for 8 months, 9 months and 17 months, were free from 

 injurious influences on both the enamel and on most of the fillings,^^ 

 whether the teeth were salivated (covered or uncovered) during the 

 intervening periods or not. 



168. The excretion of creatin during a fast.^o F. D. Zeman 

 and Paul E. Howe. Recent criticism^^ of results obtained with 

 Folin's method for the determination of creatin in urine, in the pres- 

 ence of acetone and aceto-acetic acid, has thrown doubt upon the 

 presence of creatin in the urine of fasting man. We have deter- 

 mined creatin in the urine of a fasting man throughout a 7-day fast. 

 The method of Graham and Poulton was employed for the removal 

 of acetone and aceto-acetic acid; quantitative determinations were 

 made of these substances, together, and of ^-hydroxy butyric acid. 

 Control experiments were made with untreated urine. Determina- 

 tions before and after the appearance of the interfering substances 

 showed the method to be accurate in their absence. Creatin was ex- 

 creted on each fasting day in amounts equal, in most cases, with those 

 obtained in previous fasts under similar conditions. 



169. Recuperation : Nitrogen metabolism of a man when 

 ingesting successively non-protein and normal diets after a 



19 The fillings consisted of the foUowing materials : malleted gold, gold in- 

 lays, gutta percha, Arnes' black copper cement, Stanle/s red copper cement, 

 Arnes' pearl white inlay cement, Arnes' berylite, fellowship alloy, Silicate cement, 

 oxyphosphate of zinc, synthetic porcelain, alloy, amalgam. 



20 Most of the work was done in the Biochemical Laboratory at Teachers 

 College. 



21 Graham and Poulton : Proc. Roy. Soc, 1914, Ixxxvii, B, p. 205. 



