DEATHS IN THE SOCIETY'S GARDENS. 185 



They have revealed an apparently definite dimorphism of the 

 schizonts in the circulating blood, a long slender form which 

 produces great deformation of the red cell, the hsemoglobin being 

 retained, and a short stout form which produces much less 

 deformity but exhausts the haemoglobin very rapidly. The 

 significance of the two forms and their relation to the schizogony 

 in the liver-cells remain to be determined by further study, for 

 which a considerable material has been preserved. 



Malignant neiv Groivths. — In two mammals death was ascribed 

 to carcinoma and in two birds to sarcoma. Of these one case of 

 squamous-cell carcinoma of the fauces and palate of a Dingo, 

 probably arising from the epithelial covering of the tonsil, has 

 been examined personally. In addition a new growth was found 

 on examination of a Leopard which died with bronchiectatic 

 cavities in the lungs. The growth in this case pi'oved to be an 

 adeno- carcinoma lying on the ventral surface of the trachea in 

 the thorax. The tissue of origin covild not be determined. 



(Two further cases have been observed in 1918: a carcinoma 

 of the liver in a Marsh-Buck and a teratoma of the testis in a 

 Golden Eagle.) 



Comparative Pathology of the Thyroid. — The special value of 

 the material occurring in the Prosectorium consists in the 

 opportunity offered for a comparative study of pathological and 

 physiological problems which are of general interest, a.nd special 

 attention has been directed to the thyroid gland. The thyroid 

 occurs throughout the -whole vertebrate series and, with the 

 exception of the cyclostome fishes, presents the same histological 

 picture in all. From studies in man and mammals in various 

 pathological conditions an important role has been asci'ibed to it 

 in the reaction of the body to a variety of intoxications. The 

 results of physiological experiment indicate other important 

 functions both in health and disease. It was therefore of interest 

 to note the contrast in the appearance of the gland in cold- and 

 warm-blooded animals respectively in severe infections. In 

 warm-blooded animals dying under these conditions extreme 

 congestion of the whole gland is piactically constant. ISTothing 

 of the kind has been encountered in the reptiles examined, 

 although a large projDortion presented severe septiceemic con- 

 ditions after death. This result is unfavourable to the view that 

 the thyroid plays- the pai't of a neutraliser of toxic substances in 

 the body. It is in much better harmony with the view that the 

 changes in the thyroid in these conditions are the expression of 

 its participation in the heat-regulating mechanism of the body. 

 In poikilothermic animals one would expect these changes to be 

 absent. 



E^ffect of Diet on the Thyroid. — Although attention has been 

 drawn to the effect of a meat diet on the thyroid, no observations 

 are recorded on the results of the natural experiment presented 

 by the occurrence of meat-eating and plant-eating groups in birds 

 and mammals. The analysis of the observations in birds presents 



