495 



xylin aolution two to twelve hours. Weigekt's borax - prussiate of 

 potassium solution is used for differentiation. The differentiation takes 

 place rapidly and must be watched carefully. 



The formalin sections of the central nervous system may also be used 

 for Ream's modification of Nissl's method, but the staining of the 

 chromatin and minute structure of the nucleus and cytoplasm is not quite 

 80 sharply outlined as with absolute alcohol fixation. 



The duration of the hardening in formalin solutions has a very im- 

 portant and varying influence on the nerve fibres and ganglion cells with 

 reference to the application of such methods as the Weigert and NissL 

 groups of stains. A further study to define the more exact limitations 

 of formalin as a new histological preservative for the nervous system 

 will be published later and the more exact periods of time in the 

 hardening necesary for different stains detailed. 



Mr. R. H. C. Cunningham, "On the sources of illumination for photo- 

 micrography," noted a practical mode of employing the arc light with 

 satisfactory results. 



Mr. C. F. Cox illustrated that the "Latest theories of diatom struc- 

 rure", exhibiting lantern slides of Mr. T. F. Smith of London. 



Dr. Edward Leaming projected a series of his micro-photographs, of 

 bacteria, fertilization processes of sea-urchin, Toxopneustes, and 

 GoLGi preparations. Bashford Dean, Recording Secretary. 



Correction. 



An unfortunate printer's error occurred in my article on ,, Movements 

 of the Nucleolus through the action of Gravity", published in X. Band, 

 No. 11, of the Anatomischer Anzeiger, p. 337 — 340. 



On page 339, Figs. 3 and 4 have been reversed. „Fig. 3" should 

 read Fig. 4, and „Fig. 4", Fig. 3. 



This error, however partially corrected by the arrows showing the 

 direction of the action of gravity, in each of the figures, tends to deprive 

 the article of the only point it was trying to make. 



Francis H. Herrick. 



Dr. Unna'S dermatologische Preisaufgabe für das Jahr 1895. 



Da der Preis für die Aufgabe des vorigen Jahres nicht erteilt werden 

 konnte, so wird dieselbe für dieses Jahr noch einmal ausgeschrieben. Der 

 Preis beträgt jetzt das Doppelte des vorigen, d. h. M. 600. 

 Die Aufgabe für 1895 lautet also wiederum: 



Es soll untersucht werden, ob und inwieweit die in neuerer Zeit 



aufgestellten Behauptungen, daß coUagene, elastische Fasern und 



ßesshafte (pigmentirte) Bindegewebszellen in die normale Stachel- 



Bchicht hineinreichen, begründet sind. 



Die Bewerbung ist unbeschränkt. Die Arbeit ist bis Anfang December 



1895 bei der Verlagsbuchhandlung Leopold Voß in Hamburg, Hohe 



