’ 
THE HISTOGENESIS OF THE ADRENAL IN THE PIG. 
BY 
R. H. WHITEHEAD, M.D. 
From the Hull Laboratory of Anatomy, University of Chicago. 
Wirtu 6 Text FIGURES. 
This paper gives the results of a study undertaken with the hope ot 
working out the histogenesis of the adrenal in a mammalian embryo, 
the pig, without any particular reference to comparative embryology. 
The great diversity of views concerning the histogenesis of the adrenal 
held by investigators of recognized ability is a striking feature of the 
literature of that organ. From the epoch-making publications of Bal- 
four down to the present time scarcely any two authors seem to be in 
complete accord. A brief reference to the teachings of some of the 
leading authorities will serve to show the extent of the confusion : 
Balfour,’ as the result of his study of fish embryos, advanced the opin- 
ion that the adrenal in amniota is developed from two anlages, a meso- 
blastic and a nervous—the latter being furnished by the sympathetic 
eanglia situated along the course of the abdominal aorta. According 
to this view, the cortex of the mature gland is derived from the meso- 
derm, while the medulla is contributed by the sympathetic ganglia. 
This hypothesis received considerable support from investigations by 
some of Balfour’s pupils, notably Mitsukuri, and is, perhaps, the most 
generally accepted of all the views. 
Gottschau? noted, as others (M. Braun, Mitsukur1) had done, the 
nearness of the first trace of the anlage, in the shape of a small cluster 
of crowded mesenchymal cells, to the inferior vena cava, and believed 
that it was derived from the mesenchyme. He held that the cortex 
and the medulla are derived from the same source. 
Janosik, having observed that the mesothelium in the region of the 
inferior vena cava and the transverse septum contributes cells to the 
mesenchyme at the point where the adrenals are formed in mammals, 
1 The Development of Elasmobranch Fishes, London, 1878. 
2 Arch. f. mikr. Anat. u. Entwick., Leipz., 1883, 8S. 412-458. 
3 Arch. f. mikr. Anat., Bonn, Bd. XXII, 1883, 8. 738-745. 
