December 28, 1917] 



SCIENCE 



643 



again revising his book, protests are already 

 being heard even from across the Atlantic. 

 Success entails responsibilities. 



L.\FAYETTE B. Mendel 

 . Sheffield Scientific School, 

 Yale UNrvERSixr, 

 New Haven, Conn. 



Occasional Papers of the Museum of Zoology, 

 University of Michigan. Nos. 1-35, 1913" 

 17 (each separately paged). Ann Arbor, 

 published by the University. 

 Dr. A. G. Euthven, the Director of the 

 Museum of Zoology of the University of Mich- 

 igan, is heartily to be congratulated upon the 

 appearance of the first volumes of these " Oc- 

 casional Papers." ISTowadays when every one 

 is continually receiving requests to subscribe 

 to some new journal or other, this series 

 comes as a refreshing delight; it is not pub- 

 lished for sale! We learn that the papers are 

 issued separately to libraries and specialists, 

 and, when sufficient matter has accumulated, 

 a title page and an index — an excellent index 

 by the way — is prepared and the volume is 

 sent forth. 



The contents will appeal especially to the 

 modernized systematist, who tries, at any rate, 

 to take interest in ecology, zoography and the 

 careful noting of life histories. "We find 

 notices not only of such astonishing novelties 

 as Lathrogecho, Pseudogonatodes and Callis- 

 cincopus among reptiles, and of Crypio- 

 hrachus and Geohatrachus among amphibia, 

 but of more general interest are the very in- 

 teresting observations upon the egg-laying 

 and hatching of several South American spe- 

 cies of amphibia, of varied genera, in all of 

 which some significant and peculiar adaptation 

 or modification is recorded. The series is not, 

 however, for the herpetologist alone. Reig- 

 hard and Cummins have a model description 

 of a new Ichthyomyzon with notes and fig- 

 ures of its appearance and customs. Other 

 writers discuss Crustacea, insects of various 

 groups, trematodes, as well as birds and mam- 

 mals. 



That these articles were not chosen for the 

 collection but simply represent the natural 



output for this comparatively new and hitherto 

 little-known museum indeed augurs happily 

 for the future of the series and for that of the 

 museum as well. Workers in the Museum of 

 Comparative Zoology at Harvard are perhaps 

 naturally more synipatico than others and 

 when they review their own museum's past it 

 is not difficult for them to foresee the swift 

 growth of another great university museum 

 of similarly unrestricted interest and endeavor 

 at Ann Arbor. 



T. Barbour 



SPECIAL ARTICLES 



CONCERNING THE INFLUENCE OF THE AGE OF 



AN ORGANISM IN MAINTAINING ITS 



ACID-BASE EQUILIBRIUM 



The importance of the maintenance on the 

 part of the blood and tissue juices of a hy- 

 drogen ion concentration within certain nar- 

 row limits of variation has been established 

 through the work of J. S. Haldane and L. J. 

 Henderson. Recent investigations have not 

 only served to emphasize the importance that 

 the organism should maintain a certain acid- 

 base equilibrium for its physiological life, but 

 have also shown that when the mechanism 

 which regulates this equilibrium is interfered 

 with so that the hydrogen ion concentration 

 of the blood is increased and maintained for 

 an adequate' time, the organism no longer 

 functionates normally, but becomes patholog- 

 ical in certain of its reactions. 



It is not the object of this note to enter into 

 a discussion of the factors concerned in main- 

 taining a normal acid-base equilibrium, nor 

 to discuss those pathological conditions in 

 which a variation from the normal is fre- 

 quently observed. The object is to call atten- 

 tion to the influence of the age of the organ- 

 ism in controlling the mechanism by which 

 the acid-base equilibriiun is kept within the 

 bounds of normality. 



Some years ago, while conducting a series 

 of experiments in which uranium nitrate was 

 employed as the toxic agent to induce an 

 acute nephritis, the observation was made that 

 this substance was more toxic for old animals 

 than for young animals.^ This variation in 



1 MacNider, W. deB., "On the Dififerenee in the 



