520 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



to the (usually) single and long process which extends along 

 the center of the nerve-fiber, and is then called "axis-cylinder; 

 "dendrites" to the cell's many processes some of which end in 

 many branches or tufts other than the neuraxon. With 

 Foster and Sherrington we will consider that neuraxons carry 

 impulses away from the cell, while dendrites transmit impulses 

 into the cell. Two other prominent morphological features are 

 the "gemmules" minute projections all along the dendrites 

 and their terminal twigs, which recall those on the stems of 

 the moss-rose, and the varicose, or irregular, swellings that may 

 be observed in the course of the dendrites or their terminal 

 twigs. 



The experiment of Demoor was briefly as follows: He 

 killed a dog by injections of morphine; a second dog was given 

 morphine for some time, then killed by cutting the medulla; 

 a third was trephined. The next day a piece of the left hemi- 

 sphere of the latter dog was removed; the animal being then 

 morphinized, another piece but of the right hemisphere this 

 time was removed. Portions of the hemispheres of the two 

 killed dogs having also been removed, all specimens were 

 treated in precisely the same manner. The cellular changes 

 were found to be similar in all specimens taken from the mor- 

 phinized animals: their gemmules had disappeared. Alone of 

 the series the piece removed before morphine had been given 

 was covered with regularly distributed gemmules. Now the 

 fact we wish to emphasize is this: while this experiment is 

 thought by its author to show that the retraction of the gem- 

 mules constitutes the inactive state, as induced by morphine 

 through the local action this drug is now thought to have upon 

 nerve-cells, the retraction of the gemmules, as we view the ex- 

 perimental result, is due to the suprarenal insufficiency (total 

 arrest of function in the dog killed with morphine) produced 

 by the toxic. And this is an important feature, since we thus 

 have, instead of a purely local effect, an example of the general 

 physiological process through which the neuron passes from 

 the active to the passive state provided the histological pict- 

 ure is not a misleading one. 



Again, the same structures treated by different methods 

 have been found to yield different results. Thus, H. H. Baw- 



