A. Section of normal liver of a dog. B. Section of liver of a dog after injection of 

 diphtheria toxin. C. Section of liver of a dog after injection of diphtheria toxin plus 

 morphin. D. Section of liver of a dog after injection of diphtheria toxin and the con- 

 tinuous administration of nitrous oxid for four hours. 



FIG. 76. THE PROTECTIVE EFFECT OF MORPHIN AND OF NITROUS OXID ON THE 

 LIVERS OF DOGS WHICH HAD RECEIVED INJECTION OF DIPHTHERIA TOXIN. 



Note the vacuolation of B and compare with the conservation of nuclei and cytoplasm 

 in C. (From photomicrographs, X 1640.) 



