340 GENERAL DISCUSSION 



displacements of the lEP and pH of the mitochondria take place in 

 the neurons of the cortex and — the least — in the motor cells of the 

 spinal cord. It is imjjortant to emphasize that the destruction of the 

 physico-chemical characteristics with pH of the mitochondria is ob- 

 served when the entire morphological structvu'e is maintained, being 

 evidently an index, and a reflection, of the functional pathology of the 

 cells. 



We ascertain : (a) the appearance of extensive cytochemical varia- 

 tions in the afferent nerve cells of mammals in the irradiation process 

 which may be recorded in the first minute after the action; (1)) these 

 destructions, which are amplified or weak or damped in a wave- 

 shaped manner, are maintained in the first hours and time periods, 

 i.e. during a latent period; (c) they are accompanied by analogous 

 increasing cytochemical and functional injui'ies of the higher centres 

 of the vegetative system (the intermediate brain, the reticular sub- 

 stance, etc.) and, partly, of the cortex of the hemispheres (cerebral 

 hemispheres) which must be considered responsible for the generally 

 knoMii manifestations of radiation sickness, for example the destruc- 

 tion of mitosis and regeneration, the derangement of blood circulation 

 and the blood system, etc.; (d) in the course of the disease, there 

 arise paranecrotic and thereafter degenerative conditions of the 

 neurons. 



We, sharing the opinion of Livanov, Bryukov, Livshits, Grigor'yev, 

 Arbuzov and others, ])elieve that in higher vertebrates the radiation 

 damage must be estimated as nerve damage, the individual links of 

 which are accessible for radiation and aetiological tlierajay. 



It is necessary to distinguish and separate the leading elements of 

 radiobiological j)rocesses which are sharply dissimilar at the cellular 

 level and in systems of the whole organism : the elementary mechanisms 

 at the cellular level prove to be, for the most part, similar (in spite of 

 the properties of diverse types of cells and the final outcome of the effects 

 caused by them); but from the moment of the emergence of a nervous 

 system, and as its functions develop and become more complex, the 

 leading element of the radiation damage consists in the destruction 

 of the nerve regulations, which comprise the direct reflex and metabolic 

 reactions. In other words, in the process of evolutionary complexity 

 a shift occurs in the "control" systems, which, in any case for verte- 

 brates, brings to the fore the "sujDercellular" correlation of the organism 

 as a whole, i.e. its nervous system in the Pavlovian sense of its function 

 as an equilibrator with the external medium ; given adequate compen- 

 satory o]:)portnnities to the nervous system, even the initial radiation 

 variations do not occur without a trace. 



