1909.] 



Organs of Rats and Mice, etc. 



291 



inconstant. Distinct hypertrophy was found, f//. in one case with a tumour 

 one-seventli of the body-weight, but the ratio fell within the normal in other 

 cases for tumours of the same size. 



Heart. — The heart is enlarged both in transplanted and in spontaneous 

 tumours. In general the enlargement is proportional to the weight of the 

 tumour {rf. Tumours " G3," " 50," rat-sarcoma, Table II). Exceptions are not 

 infrequent. Rapidly growing tumours, e.g. " J," do not give so marked 

 hypertrophy as those which grow more slowly with a richly developed blood- 

 supply, ('.(/. '• Tximours " 50 " and " 39." The mechanical factors are in all 

 probability mainly responsible. The pi'egnant normal animals examined 

 did not present a corresponding enlargement of the heart. 



Kidney. — The kidneys of tumour mice (and pregnant mice) showed only 

 minor variations such as are met with in normal animals. The transplanted 

 rat sarcoma, on the contrary, induced constantly an increase in the size of 

 these organs. The enlargement could be recognised with the naked eye in 

 animals with large tumours, and the weights were found to be double the 

 normal expectation in many cases. This enlargement was directly proportional 

 to the size of the tumours, as in the case of the liver and heart. The 

 sarcomata of the Mouse " 92," " 37 sarcoma," " 100 sarcoma," did not produce 

 this change. Therefore it is not characteristic of the sarcomata. 



Microscopical examination of the enlarged kidneys showed hyperjemia, 

 with here and there haemorrhages and degenerated cells. Mitoses seemed 

 to be more frequent in the tubular epithelium than in normal kidneys. 



Lung. — The results are inconstant. In one and the same strain normal 

 and enlarged lungs are found and constant alterations are not produced. 



Spleen. — As in normal animals, the spleen is subject to enormous 

 individual variations in tumour-animals. Although exceptionally large 

 spleens were found in many cases {e.g. Tumours " 173," " B "), it is 

 impossible to refer the hypertrophy to the presence of the tumours. 



In conclusion, we desire to express our indebtedness to the Executive 

 Committee and Director of the Imperial Cancer Research Fund for the 

 facilities afforded for this investigation. It is a pleasure to acknowledge the 

 assistance and interest of Dr. Bashford and his Assistants, Drs. Murray, 

 Haaland, and Eussell, and of Dr. Cramer. 



Sumviary. 



Weighing experiments on 200 rats and mice bearing tumours (13 trans- 

 plantable and four spontaneous mouse tumours, 2 transplantable rat 

 tumours) have shown : — 



