78 ILLINOIS ACADEMY OF SCIENCE. 



Stages of radium irritation sections show evidences of prolifera- 

 tion of the tissue elements, such as indicate an over-stimulation of 

 the cells by a peculiar irritant. These changes are most marked 

 in the tissues of greatest functional activity. At first there are 

 an increased production of pigment, and an exaggerated proHfer- 

 ation of the germinal and younger (deeper) cells of the epidermis, 

 and especially of the follicles of the epidermis ; in the corium, or 

 body of the skin, there are dilatation of the capillaries, an infiltra- 

 tion of round cells, and oedema — the changes of inflammation. 

 Later the changes become exaggerated ; there is proliferation of 

 the inner layer of the blood vessels (an obliterating endarteritis) ; 

 the round-cell infiltration becomes intense ; the connective tissue 

 fibres are ©edematous and stain poorly. In the epidermis the 

 cells show extreme degenerative changes ; they become vacuolated, 

 the nuclei are fragmented, there is degeneration of the cytoplasm 

 so that stains are taken poorly, and complete breaking down of 

 many cells ; these changes are especially intense in the highly 

 specialized and active cells of the appendages of the skin — the 

 hair follicles and the sweat and sebaceous glands — and they may 

 result in the obliteration of these structures, a phenomenon which, 

 occurring as it may without destruction of the surrounding tissues, 

 is not produced by any other known agent. In the last stage in a 

 radium reaction there is necrosis of the affected tissues, the con- 

 nective tissue stroma being the most resistent and last to break 

 down. 



In diseased tissue in the skin such as epithelioma (cancer) and 

 lupus (tuberculosis), there is the same sort of reaction; it is also 

 found that the pathological tissues which are composed of grow- 

 ing cells, often of embryonic type, react in the same way as the 

 active sensitive tissues of the normal skin. They are more sensi- 

 tive to the effects than the stroma in which they are growing, 

 disintegrate or degenerate readily, and are destroyed before or 

 without destruction of the connective tissue around them. 



It is evident in this process that we are deahng with an agent 

 whose results are produced by influencing the biological processes 

 of the cells themselves. The effects are not produced by an 

 immediate destructive action of the rays, as a heat burn for 

 example is produced. There is no immediate effect from the 

 application of radium; it is only after days, it may be two or 

 three weeks, that the effects appear. The inference is that the 

 radiations set up some process in the tissues which itself ends in 



