2. Endocrines and Populations 195 



of the adrenal glands, but a brief summary of the particularly useful and 

 more recent publications on the subject will be given. The books which 

 already have been listed discuss the adrenals of a large number of species, 

 but the descriptions and illustrations are limited. However, the histology 

 and histochemistry of the adrenals of a few species are discussed in con- 

 siderable detail in a number of papers. The recent publications of Elias and 

 Pauly (1956) and Pauly (1957) describe the microscopic anatomy of the 

 adrenal glands of laboratory rats and humans. These papers are well 

 illustrated, and the stereographic reconstructions of serial sections are 

 helpful in understanding the adrenal morphology of these two species. One 

 of the important facts brought out in these papers is that the adrenal cortex 

 of the rat is not arranged in cords as it is in humans and monkeys. The 

 parenchyma of the rat adrenal cortex is a continuum which is tunneled by 

 vascular channels. A number of additional papers deal with the anatomy, 

 circulation, or histochemistry of the adrenals of laboratory rats, especially 

 with regard to function, zonation, and reactions to various stimuli (Howard, 

 1938; Flexner and Grollman, 1939; Greep and Doane, 1947, 1949a; Deane 

 et al., 1948; Deane and Morse, 1948; Cain and Harrison, 1950; Feldman, 

 1950, 1951; Cater and Stack-Dvmne, 1953, 1955; Josimovich et al, 1954; 

 Jones and Spalding, 1954; Jones and Wright, 1954a, b; Christianson and 

 Jones, 1957), and other more general papers on the histochemistry and 

 function of the adrenals are based largely on material from laboratory rats 

 (Dempsey, 1948; Greep and Deane, 1949a, b; Sayers and Sayers, 1949). 

 The differences in morphology between the adrenals of wild rats {Rattus 

 norvegicus and Rattus alexandrinus) and those of Norway rats from the 

 laboratory have been described by Rogers and Richter (1948), and the 

 histology of wild and laboratory Norway rats has been described and com- 

 pared by Mosier (1957). A comparative study of the vascularization of 

 the adrenals of rabbits, rats, and cats has been made by Harrison (1951) 

 and followed by a description of the adrenal circulation and its regulation 

 in the laboratory rabbit (Onjctolagus) (Harrison, 1957). 



The histology of the adrenal glands of the prototherians Onuthorlnjnchus 

 and Tachyglossus has been described in considerable detail by Wright et al. 

 (1957). The bulk of the chromaffin tissue was found in the lower pole in 

 these species rather than in the more usual central position. The cortices of 

 these species also differ considerably in their histologic appearance from 

 those of eutherians. We have mentioned above that the adrenals of North 

 American soricids have strikingly little cortical tissue, although a critical 

 study of this material has not been made (J. J. Christian, unpublished) . 

 Lanman (1957) has described the fetal zones of the adrenals of the fol- 

 lowing fetal or neonatal primates: macques (Macaca midatta) , potto 

 {Perodicus putto) , chimpanzee (Pan sp.), hybrids of Cercopithecus {Cerco- 



