s. Vincent, The Comparative Histology of the Suprarenal Capsules. 283 



chemistry of the suprarenal capsules [118—121, 81, 82] I thought it 

 would be interesting to employ the results obtained from these modes 

 of investigation to form a basis for a widely comparative survey of the 

 structure of the representatives of the capsules throughout the Vertebrata. 



The literature of the subject is very extensive, and although I 

 have tried to obtain access to every paper bearing upon it, I fear 

 there may yet be some omissions, which will I hope, be pardoned. 



A full account of the history up to date as regards Pisces, will 

 be found in the paper above referred to [116], and some account of 

 the literature in Amphibia and Eeptilia in 117. The results here put 

 forward embody the labour of five years, and some repetitions of 

 former published results have been necessary for the sake of uniformity 

 in a review of the whole subject. 



I have examined a very large number of species. As in pre- 

 vious histological work, I have relied entirely upon perfectly fresh 

 material, except in the case of some of the rarer animals. Some 

 preparations were made quite fresh, others after freezing. Still others 

 after hardening, were stained in bulk imbedded in paraffin, and cut 

 witli the "Rocking Microtome". The fixing and hardening fluids I 

 have employed most frequently are Müller's fluid, and other bichromate 

 solutions, alcohol, formol, mercuric chloride, and osmic acid. Methods 

 of dissociation have been employed for studying the separate cells, 

 and the most frequently used of these was maceration in Eanvier's 

 ^/■5 alcohol. The most useful fluid for hardening is undoubtedly Müller's, 

 because by this means we have a universal method of distinguishing 

 cortex from medulla. 



I take this opportunity of expressing my thanks to Professor 

 E. A. Schäfer, LL. D., P. E. S., for advice on many points connected 

 with this research, and for the generous manner in which he has placed 

 the resources of his laboratory at my disposal. I am also indebted 

 to Professor G. B. Howes, LL D., F. E. S., and to Dr. H. 0. Forbes 

 for their kindness in fmmishing me with material. I have further to 

 record my gratitude to the British Medical Association, by whose 

 munificence I have been enabled to carry on my researches during 

 the past two years. 



