572 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



nervous structures via the axon is evident; but do lymph- 

 spaces connected with veins actually receive this blood? Re- 

 ferring to the effects of acute alcoholic poisoning upon the 

 veins, Berkley says: "Changes in the coats of these vessels are 

 similar to those in the arterial system, but aggregations of 

 dying polynuclear corpuscles are more frequent, and are by far 

 the most striking feature both of their contents and surround- 

 ings. These aggregations, which may vary from three or four 

 to a dozen or more, are located both within and without the 

 lumen of the vessel (especially the smaller ones). Within the 

 lumen are collections of white corpuscles filling the interior, 

 and numbers are seen penetrating the walls. So vast are the 

 collections in the perivenous spaces that the whole cavity is 

 occasionally filled, and backward pressure from the plugs and 

 compression of the vessel from the outside have attained such 

 a height that in a number of instances the vessel's walls have 

 ruptured and red corpuscles are intermingled with the white 

 and fill the space completely." These features are well illus- 

 trated in the annexed photographs. The center of Fig. 8 shows 

 "polynuclear leucocytes in the perivascular space of a small 

 intermediary vessel compressing its walls," while Fig. 9 shows 

 "leucocytes in the blood in a cross-section of a large vein." The 

 fact that the leucocytes are found in the "perivenous spaces" 

 and "within the lumen of the vessel," coupled with the ob- 

 servation that they are "seen penetrating the walls," so clearly 

 point to the process involved that further evidence seems un- 

 necessary. The blood (we have seen that even red corpuscles are 

 present) of the axon evidently finds its way into a lymph-space 

 connected with a vein } thence to the general circulation. 



Still, there is a feature of the whole process which requires 

 elucidation. Why should the veins, which, of course, com- 

 municate with channels through which the blood can be freely 

 evacuated, become engorged under the influence of the adrenal 

 stimulation induced by alcohol? Engorgement of the arteries, 

 their capillaries, the neuroglia channels, and the dendrites is 

 a normal consequence of adrenal stimulation; but, the veins 

 being outlets, such is not the case with the venous engorge- 

 ment. This anomaly is accounted for by the now generally 

 admitted fact that the vessels of the cerebral substance per se 



