136 



r. DEVIK 



following the application of the carcinogens (Fig. 2). On the other hand, there 

 was no clear indication of any initial decrease, as with the non-carcinogenic 

 compounds. 



One main difference between X-radiation and toxic or pharmaceutical 

 substances is the distribution in space: the former acts very uniformly at the 



.9 E 



> 1- 



■>.$ 



5-0 



30 

 2-0 

 I -5 

 1-0 

 07 



0-4 

 0-2 



'Controls. Sham treated animals 

 EPIDERMIS 



13 17 II 14 21 28 35 42 

 1 5 



Time (days) 



5-0 



3-0 



2-0 



1-5 



1-0 



07 



0-4 



0-2 



Benzene 

 EPIDERMIS 



SOr 



:317 

 1 5 



II 14 21 28 35 42 



S 0-4 



^■^rO-S% l.2-Benzanthracene 

 30- 

 2-0- 

 1-5- 

 l-0« 

 07^ 



0-2 





;3:7 

 1 5 



114 21 28 35 42 



5-0 



30- 



2-0 



1-5 



10 

 07 



0-4 

 0-2 



0-5% Phenanthrene 

 EPIDERMIS 



1% 3-Methylchoianthrene 

 EPIDERMIS 



3 17 II 14 

 1 5 



0-5%9,10-Dimethyl- 



1.2-benzanthracene 



EPIDERMIS 



i3i7 1114 

 1 5 



21 28 35 42 



Time (days) 



35 42 



Fig. 1. Formazan deposition in the epidermis after application of three non- carcinogenic 

 compounds (to the left), and tlu'ee carcinogenic compounds (to the right), relative to the 

 deposition in normal epidermis. Reproduced by kind permission of Dr. 0. H. Iversen (Iversen 

 and Evensen, 1962). 



cellular level, whereas the latter are expected to show differences in concen- 

 tration both at the cellular, and the subcellular, level. For this reason one 

 should not expect too close a j)arallelism neither with respect to the acute nor 

 to the late reactions and effects. 



