9 6 



Scientific Proceedings (91). 



or low phthalein output. From these observations we conclude 

 that 20 mg. per 100 c.c. may be taken as upper normal limit of 

 urea nitrogen in the blood of hospital patients. 



166 (1344) 

 Production of transplantable growth. 

 By Rhoda Erdmann. 



[From the Osborn Zoological Laboratory, Yale University.] 



After analyzing the known numerous theories on the origin 

 of abnormal growth and especially of malignant growth, which 

 have been devised either with or without reference to facts, it seems 

 possible to concentrate the apparently necessary postulates for the 

 successful origin of abnormal growth to the following conditions 

 which cover all important theories on this subject. The presence 

 of a cell group in an indifferent stage of growth, the dissociation of 

 this cell group from its surrounding and its change from the 

 indifferent stage of growth to a stage of proliferation, the in- 

 flammation of the connective tissue, neighboring this cell group, 

 and a changed metabolism of the cells, in which this cell penetrates 

 and which it destroys. Supposed these conditions are true to 

 actual facts it must be possible to produce experimentally these 

 factors either in various sequence or all at once and observe results. 



I. Embryonic tissue of the chicken heart, after twelve days' 

 incubation, was cultivated in a plasma medium for three days, 

 and three 1 mm. square pieces implanted subcutaneously into a 

 chicken. The implants produced after ten days small protuber- 

 ances. Sections show cyst formation, caused by the isolation of 

 the epidermis above the implants and inflammatory proliferation 

 of the connective tissue of the host. Cyst formation, destruction 

 of the feather follicles and accessory apparatus of the feather after 

 previous isolation of the feather-forming complexes are visible. 

 The implanted embryonic heart-muscle tissue which is surrounded 

 by lymphocytes and newly formed connective tissue cells shows no 

 considerable development. Protuberances produced in the same 

 manner disappear after three weeks, as was to be expected. 



