20 



Mr. C. H. Kellaway. The Effect of Certain 



fats and lipoids of the cortex, and the osmic vapour method more recently- 

 used by Cramer (1918). Some of the frozen sections, prepared after treatment 

 with bichromate solution, were stained with haematoxylin and eosin. 



In addition to the changes described by McCarrison, most of which I have 

 also noticed, there are two additional points which may be of importance. 

 In the first place, the cortical enlargement appears to be accompanied, not 

 only by degenerative nuclear changes, but also by a loss of definition of the 

 lipoid granules present in it. This is well seen in frozen sections stained with 

 Scharlach, K. 



Secondly, the enlargement of the cortex appears to interrupt the con- 

 tinuity of the normal network of medullary substance, and gives it an 

 appearance on section of a number of isolated nodes surrounded on all sides 

 by swollen cortical tissue, and only connected with each other by fine strands 

 of tissue. This appearance is well shown in the osmic vapour preparations 

 which have been kindly photographed for me by Mr. Barnard (Plate 1, 

 figs. 2 and 3). 



Finally, it is of interest to record that the adrenals of pigeons fed on 

 polished rice, with the addition of a daily ration of " marmite," differ histo- 

 logically in no important respect from those of normal birds. 



These histological appearances suggest two possible ways in which the 

 output of adrenaline into the blood stream might be hampered or prevented 

 in pigeons on such deficiency diet. The presence of degenerated sympathetic 

 ganglia described by McCarrison indicates the possibility that the splanchnic 

 fibres to the adrenals might also be degenerated, though I have not been able 

 to show that this is the case. If this were so, the output of adrenaline from 

 the glands would be greatly diminished (Elliott, 1912). On the other hand,, 

 the cortical swelling might conceivably act mechanically, by hampering the 

 venous outflow from the gland, and so diminishing the output of adrenaline. 



The SignificaTice of Adrenal Enlargement of Pigeons fed on Polished Pice. 



Various factors may come into play in causing the adrenal enlargement 

 which occurs in pigeons fed on polished rice. Histological observations seem 

 to exclude congestion of the glands as a constant factor in the production of 

 this effect. Apart from congestion, some oedema of the gland tissues is 

 consistent with the histological appearances presented by them, and part of 

 the increase in weight is explained by an increase in the water-content of the 

 adrenals. 



The weight of the freshly dissected-out adrenals of a normal pigeon was 

 23'0 mgrm., and when these were dried to constant weight over sulphuric 

 acid in vacuo they weighed 7-0 mgrm. The percentage of water in these 



