262 THE ACTION OF THE LIVING CELL 



homologous cytost intramuscularly directly adjacent 

 to the sciatic or ulnar nerve resulted in the onset of 

 a condition resembling neuritis and causing marked 

 sensitivity and lameness, the duration of v^hich in any 

 individual case was found to depend upon the amount 

 of cytost injected. The accompanying photograph 

 (Fig. 16) shows a cat suffering from neuritis of the 

 hind limbs induced by this means. 



Microscopic examination of the affected nerves 

 showed that the injections of cytost had caused con- 

 gestion and extension of the vessels in the tissues sur- 

 rounding the nerves and in the nerve sheath, although 

 the nerve itself did not appear to be affected. This is 

 shown in figure 17, wherein one may clearly discern 

 three areas distinctly showing this fact. The onset of 

 neuritis in the experimental animals is probably to be 

 attributed to the stagnation caused by the cytost, which 

 then causes extension of the vessels and consequent 

 pressure upon the nerve, rather than to any direct ef- 

 fect upon the nervous tissue. 



The results of these simple experiments indicate 

 that cytost intoxication may actually be an important 

 causative factor in the occurrence of analogous condi- 

 tions in man. If this be the case, how is one to diagnose 

 and treat patients suffering from this cause? 



The diagnostic procedure is of necessity somewhat 

 unsatisfactory. First, of course, one must examine the 

 patient in order to ascertain the absence of any gross 

 pathologies which may give rise to the cytost, and these 

 must be cleared up by the usual medical and surgical 

 procedures. The writer has found that intramuscular 

 injections of homologous cytost at the site where pa- 

 tients complain of pain frequently leads to a marked 



