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



reflux condenser with boiling absolute alcohol. This treatment, in addition 

 to removing all the fat, was efficient in removing the water soluble B, as will 

 be shown by the experiment here described. 



Two series of birds were fed, with the addition in Series 8 of 1 grm. of 

 fat-free casein, and in Series 9 of 1 grm. of fat-free casein, and 1 grm. of 

 " marmite " daily to the diet of poUshed rice. The birds of Series 8 rapidly 

 acquired polyneuritis, while those of Series 9 remained normal. Table VII 

 gives the results obtained. 



The birds of these series were kept for about a month in the laboratory 

 before the experiment was started, and the figures obtaiued are comparable 

 with those obtained from the second series of normal birds in Table II. 



The effect of the yeast extract in preventing adrenal hypertrophy in 

 pigeons fed on polished rice is evidently not due to any protein or protein 

 derivatives, which are present in small amount in such a ration, but to the 

 water soluble B, which is present, though the influence of the salts in such a 

 yeast extract is not excluded. 



On the other hand, the addition of " marmite " to the casein-rice diet does 

 not perceptibly prevent increase of the store of adrenaline, the figures for 

 Series 8 and 9 being nearly identical, though the dose was adequate to 

 prevent such increase in birds fed on a basic diet of rice alone. It becomes 

 increasingly evident that the exhibition of symptoms of polyneuritis is not 

 related to the increase in content of adrenaline, which occurs as a result of 

 feeding pigeons on polished rice. 



The Histology of the Adrenals of Polyneuritic Pigeons. 



McCarrison (1919, a) has already made some important observations on 

 the histological appearances presented by the adrenals of pigeons fed on 

 polished rice. The chief points to which he has drawn attention are : the 

 disproportionate enlargement of the cortex as compared with that of the 

 medulla in these glands ; the presence of congestion, which is neither 

 sufficiently constant nor pronounced wholly to explain the enlargement ; 

 the occasional broken down appearance of the central part of the gland, 

 together with general nuclear changes in both cortex and medulla, which 

 suggest degeneration ; and, finally, the degeneration which is sometimes 

 present in sympathetic ganglia adherent to the gland. 



I have examined the adrenals of a few normal and experimental pigeons in 

 order to see if any further light could be thrown on the cause of the changes 

 which occur in them as a result of deficiency diets. I have used two special 

 methods of staining, the bichromate method of Kohn as described by Elliott 

 and Tuckett (1906), using Scharlach, E, as a selective counterstain for the 



