370 C. DA FANO 



tumours of small laboratory animals are at first invaded by 

 elements of the lymphocytic type and then by connective-tissue 

 cells, the process generally ending in the complete disappearance 

 of the tumour cells and the production of a scar structurally 

 similar to that seen during the healing of certain inflammatory 

 lesions of the subcutaneous connective tissue. When studying 

 the apparatus of absorbing tumour cells, that of some of the 

 elements taking part in the production of the scar was observed 

 and will be also briefly described. 



Material and Methods. 



The following malignant new growths in various phases of 

 spontaneous absorption were examined : 



Mouse. 

 Jensen. Alveolar carcinoma. 

 Twort. Alveolar carcinoma. 

 27. Papillary cystic adeno-carcinoma. 

 91. Haemorrhagic and cystic alveolar carcinoma. 

 113. Slightly haemorrhagic alveolar carcinoma. 

 155. Fissure forming adeno-carcinoma. 

 206. Alveolar carcinoma. 

 630. Squamous cell carcinoma. 

 37 S. Spindle cell sarcoma. 



Eat. 



Eat 9. Adeno-carcinoma with dense hyaline stroma. 



All tumours were investigated by the cobalt nitrate method 

 with the precautions suggested in the previous work. A certain 

 number of tumours were likewise investigated by the modifica- 

 tion of Veratti's potassium antimoniate method previously 

 described. But this time the results obtained were not so 

 satisfactory as when investigating the apparatus of growing 

 tumours. This was probably due to the fact that absorbing 

 new growths often contain only a small number of healthy cells 

 and a great deal of detritus which becomes so intensely im- 

 pregnated by the potassium antimoniate method as to render 



