1907.] Implantation of Actively Proliferating Epithelium. 549 



Table II. — Control Experiments in which Healthy Living Skin of the Eabbit's 

 Ear was implanted subcutaneously. 



No. of 

 experiment. 



Duration of 



Condition of implanted skin at end of period of 

 implantation. 



implantation. 



Condition of 

 epithelium. 



Mitoses in 

 epithelium. 



Necrotic 

 epithelium. 



1 

 2 

 3 



■4 

 5 

 6 

 7 



days 



7 



7 



31 



31 



31 



31 



135 



In part living 



None living 



In part living 



None living 

 Very little living 



Very scanty 

 Yery scanty 



Absent 



Present 



In order to be in a position to interpret some of the appearances found in 

 the area of implantation, a third series of five implantations was made with 

 normal skin of the rabbit's ear, previously kept for two months in absolute 

 alcohol. These experiments will be referred to later. 



When actively proliferating epithelium was implanted it was found that, 

 during the first fortnight of implantation, such portions of the basal prickle 

 layer as remained living continued to divide rapidly, so that in the implanted 

 epithelium mitoses were about as numerous as before implantation, while, in 

 addition, loose horny epidermic scales were produced in abundance at the 

 free surface of the epithelium. The circumstance that cell division continued 

 for a time apparently undiminished in implanted actively proliferating 

 epithelium was quite unexpected, for although it is known that normal 

 epithelium preserved in a moist chamber may remain, for as much as a 

 fortnight after removal, living and capable of being grafted on to a healthy 

 granulating surface,* nevertheless such survival seems to be regarded, not 

 unnaturally, as a species of suspended animation, unattended with active 

 growth. Normal epithelium is, however, owing to its relatively slow growth 

 and its scanty amount, unsuitable for determining the effect of implantation 

 on cell activity, while the use of actively proliferating epithelium, on the 

 contrary, enables this effect to be readily ascertained. The proliferating 

 epithelium, after implantation, would appear to possess a restricted supply of 

 nourishment, for it is not possible to recognise capillaries penetrating into 

 the implanted skin, even at the end of the first week. The character of the 



* K. Garrey, " Transplantationen in der Chirurgie," ' Verhandhmgen der Gesellschaft 

 Deutscher Naturforscher und Aerzte/ 1906, Erster Teil, S. 205. 



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