770 Dr. J. BEARD, 



such as to give him the insight into the real facts, which my prepa- 

 rations have afforded me. He has given very beautiful figures, though 

 they hardly give an idea of the extreme beauty of the organ as seen 

 in good vertical sections. Leydig considered the columns as composed 

 of connective tissue and ganglion-cells. Thus his description is not 

 incorrect, for between the columns there is a quantity of connective 

 tissue, and also capillaries, and by these two tissues the smell-bud 

 gangHa are separated from one another. 



But Leydig appears to have drawn the olfactory nerve as pas- 

 sing downwards between the columns (23, fig. 7); this is not correct, 

 the nerve fibres end in the bases of the ganglionic columns as shown 

 in my figure. 



Born (6, p. 214), in the last of his memoirs on the nasal 

 cavities etc. has also seen and given an interpretation of these co- 

 lumns. 



He says: „In der zwischen den Fasern hegenden kleinzelhgen 

 Masse meint Leydig »zweierlei Zellenarten unterscheiden zu können, 

 solche nämlich, welche als Bindegewebszellen anzusehen wären, und 

 andere, denen eine nervöse Natur zukommt, die- somit kleine Gang- 

 lienkugelu vorstellen könnten«. Diese Deutung des kleinzelligen Ma- 

 terials zwischen den radiären Fasern ist, wie die Entwicklungsgeschichte 

 mit Sicherheit (!) lehrt, eine irrthümhche (?), dasselbe ist vielmehr die 

 zellige Ausfülluugsmass e einfacher Drü sen von birnför- 

 miger Configuration, die dicht an einander gedrängt die ganze Schleim- 

 haut durchsetzen." 



Although Born has seen and examined this structure of the 

 Ophidian Jacobson's organ in embryos of many stages, he has given 

 figures which are of no value to the independent reader in judging 

 of the accuracy of Born's statements. The figures are simple black- 

 board drawings without the representation of cells or nuclei of any 

 sort. Born's conclusions are quite wrong, as Ramsay Wright (34, 

 p. 389 et seq.) has already pointed out. 



So far as Wright's account*) goes, it agrees with my own. He 

 had only examined the organ in an advanced embryo (head 6 mm) 



1) Wright mentions a fuller paper by Macallum to follow his. 

 I only got a sight of this after my work was written. It is buried in 

 the Proceedings of the Canadian Institute, Toronto. Macallum does not 

 appear to have got further than Wright, and in his paper I could 

 find no statements of importance which were not already contained in 

 Wright's note. 



