930 



SCIENCE. 



[N. S. Vol. XIV. No. 363. 



variations synchronous with those of the Arc- 

 tics. 



The general conclusions are that in the Arc- 

 tics the eighteenth century was a period of very 

 marked advance of the glaciers, that this was 

 preceded by several centuries of great retreat, 

 and followed by a small retreat which is still in 

 progress. Where the information is sufficient 

 these conclusions are fully established ; where 

 it is meager they are partially confirmed or at 

 least not contradicted. 



M. Rabot points out certain resemblances and 

 diflferences between the variations of the arctic 

 glaciers and those of the Alps. Although, so 

 far as can be made out, there seems to be a fair 

 accord in the dates of the variations, there 

 seems little relation between their respective in- 

 tensities. The general advance of the arctic gla- 

 ciers in the eighteenth century was not marked 

 in the Alps ; and the strong retreat of the 

 second half of the eighteenth century in the 

 Alps is but faintly shown in the Arctics. More- 

 over, it has not been possible to show a distinct 

 relation between the variations of climate and 

 the variations of the glaciers in the Arctics as 

 has been done in the Alps. 



M. Rabot has accomplished what must have 

 been a laborious task, and deserves the thanks 

 of all persons interested in the variations of 

 glaciers. 



Harry Fielding Reid. 



Geological Laboratory, 

 Johns Hopkins University. 



The Brain of Acipenser. A Contribution to the 

 Morphology of the Vertebrate Brain. By J. B. 

 Johnston, Professor of Zoology, West Vir- 

 ginia University. Zool. Jahrb., Abt. f. Anat- 

 omie, Bd. XV., Jena, 1901, pp. 204, with 12 

 plates and 22 text- figures. 

 The application of the cell theory to the nerv- 

 ous system (for this is what the doctrine of 

 the neurone amounts to in the upshot) has 

 reached its consummation only within the past 

 decade. Accordingly, the neurology of to-day, 

 whether human or comparative, demands not 

 merely topographic descriptions of the tracts 

 and nuclei within the brain, but the precise 

 relations between the two, stated anatomically 

 in terms of cellular morphology as well as in 

 terms of experimental pathology. This necessi- 



tates the rewriting of some chapters in the 

 standard text-books and the repetition of many 

 classical researches upon the lower animals 

 with ' modern neurological methods.' 



Such, then, is the motive which has led Pro- 

 fessor Johnston to attempt ' a complete study 

 by modern methods of the brain of a lower 

 vertebrate.' The type chosen, the sturgeon, 

 was described in 1888 by Goronowitsch, and the 

 present study aims to fill in the cellular details 

 upon the basis of the topography as there laid 

 down (with the result, we may add paren- 

 thetically, of correcting several errors both of 

 fact and of morphological interpretation found 

 in Goronowitsch's account). Standard histo- 

 logical methods — among which judicious stain- 

 ing with Delafield's hsematoxylin is still un- 

 rivaled for lower brains — were, accordingly, 

 supplemented by the use of methylene blue in 

 various forms and by chrome silver impreg- 

 nation. The author's results with the latter 

 method are especially brilliant. He has suc- 

 ceeded in getting whole brains impregnated 

 and cut into unbroken series of sections, so that 

 the courses of the more important tracts could 

 be controlled by the actual demonstration of 

 the paths of individual fibers through them. 



Of the 12 plates accompanying the paper, 

 one is a chart showing all the more important 

 fiber tracts in the brain of this fish elucidated 

 by an ingenious color scheme, the reflex arc 

 being represented as consisting of a chain of 

 several links which are indicated by colors of 

 the spectrum, sensory roots blue and motor 

 roots red, with the connecting tracts in series 

 between. The other plates (all photographic 

 reprodactioasfrooiuntoucheduegatives) include 

 seven views of the entire brain, 56 photographs 

 of Golgi preparations, illustrating nearly all 

 the important types of neurones in the brain, 

 and 21 transverse sections from a series stained 

 with Delafield's hsematoxylin to illustrate the 

 topography. The latter are accompanied by 

 lettered outline drawings on transparent paper 

 and incorporate also some results of the study 

 of Golgi sections. 



Dr. Johnston is one of the few neurologists 

 who give evidence of an adequate appreciation 

 of the importance of the peripheral nervous 

 system as furnishing the key to the central, and 



