74 



the case of a widely comparative problem, when there are others at 

 our service to check our results and guide us to our conclusions. 



This observer has apparently never been struck by the immense 

 diflerence in appearance and structure between the two portions of 

 the mammalian organ, nor by the fact that these two constituents are 

 equally present in Birds, Reptiles, and Amphibia, and are in all these 

 readily to be distinguished by histo-chemical methods. He has, to all 

 appearances, not yet learnt that from the medulla only of the 

 mammalian organ can an extraordinary substance be extracted possessed 

 of eminently characteristic physiological and chemical properties, no 

 such substance being obtainable from the cortex, and that this holds 

 good for the two separate glands in Elasmobranch fishes, 



I have already pointed out in previous papers how the develop- 

 mental stages of the suprarenal in the higher Vertebrates, as recorded 

 by many competent observers, shew a parallelism with the conditions 

 found in the ascending series of the Vertebrates. In Fishes the two 

 constituents are quite separate, in Amphibians come into contact, in 

 Reptiles are beginning to be intermixed, in Birds, cortex and medulla 

 interlacing, while in Mammals the medulla is surrounded by cortex. 



I cannot understand how this writer would attempt to explain 

 the presence of the same very remarkable substance in the paired 

 suprarenal of Selachians and in the medulla of mammalian suprarenal, 

 as shewn both physiologically and chemically. Nor can I conceive 

 how he has been so bold as to put lightly aside the statements of 

 several observers that intermediate forms between nerve-cells and 

 suprarenal medulla cells are observed, and to dismiss as erring the 

 results obtained by Leydig, Balfour, Braun, Rabl, Mitsukuri, 

 Inaba, and others. 



Upon the evidence before us, I do not imagine that many 

 morphologists or physiologists will be found to accept the views of 

 Dr. AicHEL. 



Papers referred to. 



The following is not intended to be a complete bibliographical 

 list. Further references will be found in Nos. 3, 11, and 31. 



1) AiCHBL, 0., Vorläufige Mitteilung liber die Nebennierenentwickelung 

 der Säuger etc. Anat. Anz., Bd. 17, 1900, No. 1. 



2) — Ueber die Entwickelung der Nebennieren bei Selachiern etc. 

 Separatabdruck a. d. Sitzber. d. Physikal.-med. Soc. zu Erlangen 

 (undated). 



3) — Vergleichende Entwickelungsgeschichte und Stammesgeschichte 

 der Nebennieren. Arch. f. mikr. Anat., Bd. 56, 1900. 



