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cancer" were kindly supplied by Mr. J. F. McEchran and 

 Mr. C. G. Dickinson. 



Macroscopic examination. — Macroscopic examination 

 shows the tumours to vary very little from the granulomata 

 already described. The most marked variation is in the very 

 large size these tumours attain in the north of Australia and 

 their great chronicity. A point to be emphasized is that in 

 the early lesions the necrotic areas are small, pale in colour, 

 and soft, while in the older lesions they are larger, darker in 

 colour usually, and harder. It is evident that the growth of 

 the tumour depends upon an enlargement of the necrotic 

 areas and an increased tissue reaction, i.e., the number of 

 necrotic areas does not increase as the tumour grows. 



The necrotic areas when separated out from the surround- 

 ing tissues are seen to have an irregular, bosselated surface 

 with some marked irregularities or "branchings." These 

 necrotic areas are typical of "swamp cancer" as of the granu- 

 lomata described above. 



Ulceration of the surface is much more extensive in 

 "swamp cancer" than in the granulomata observed in 

 Southern Australia. 



Microscopic examination. — The histological picture is 

 essentially that of a granuloma. There is an increased produc- 

 tion of fibrous tissue, which varies with the age and size of the 

 lesion. The tumour is extensively invaded with eosinophile 

 leucocytes. There are collections of mononuclear cells, and an 

 epitheloid (endothelial) cell reaction with, at times, the forma- 

 tion of many multinucleated cells. Necrotic areas occur 

 throughout the tumour, and in the older lesions they are more 

 or less encapsulated. When ulceration of the surface is 

 extensive, neutrophile leucocytes are attracted to the part. 



This histological picture is almost identical with that 

 described in the present communication for habronemic granu- 

 lomata occurring in Southern Australia. The only variation 

 is due to the earlier and more extensive ulceration and 

 secondary infection of the superficial parts of the tumour. 

 This gives rise to an infiltration of the tissues with neutrophile 

 leucocytes, which are found mainly in the more superficial 

 parts of the lesion, but are not seen attacking the caseous 

 areas. The tissue reaction is very marked, being greater the 

 larger the tumour. 



The caseous areas have the same microscopic appearance 

 as those already described, but calcification has not been 

 observed in "swamp cancer." 



No very early lesion has been examined, so that it has 

 not been possible to demonstrate any larval Nematode: In 

 some cases spaces resembling worm canals have been observed. 



