FUNCTIONS OP THE LACRYMAL GLANDS. 269 



nerve, on the other. The reflex contraction produced in the 

 vessels and the consequent rise of blood-pressure continue as 

 long as the downward reduction of tissues by slicing progresses. 

 As soon as the medulla is reached, however, signs of impaired 

 activity appear: the blood-pressure becomes reduced, and 

 gradually sinks to naught when a certain level is reached. 

 Again, as is well known, division of the spinal cord immediately 

 below the medulla is followed by dilation of the entire vascu- 

 lar system and a corresponding decline of the blood-pressure, 

 while electrical stimulation of the cut surface of the lower seg- 

 ment is followed by general vascular contraction and a propor- 

 tionate rise in the blood-pressure. We can safely assume, 

 therefore, that removal of the stellate ganglion modified the 

 effects of the poison, because it severed the connection between 

 the terminal fibers in the lacrymal glands acting as vasocon- 

 strictors, and their center in the medulla. 



That it was only under the influence of excessive stimula- 

 tion that the lacrymal glands showed their abnormal condi- 

 tion, however, is shown by the fact that in each of the three 

 animals the organ on the operated side remained normal when 

 not under the influence of the drug. And yet it would seem 

 as if, the vessels having lost on that side their tonic contrac- 

 tion, some morbid evidence of this fact should appear. That 

 it did not suggests that the sympathetic fibers are not dis- 

 tributed to the intraglandular vessels, but to the arteries and 

 arterioles outside the gland, as in the case of the muscular 

 fibers. Indeed, the vessels that are supplied with muscular 

 walls, small arteries, and arterioles, and to which nerve-fila- 

 ments are distributed, do not penetrate the glandules; dimin- 

 utive capillaries alone reach them, along with fine nervous 

 filaments. We thus have two distinct kinds of vascular supply 

 connected with the gland: an internal system of capillaries, 

 the walls of which, as elsewhere, contain no muscular fibers, 

 and an external system of small arteries or arterioles which 

 are supplied with a muscular coat. The fact that the gland 

 on the operated side remained normal in the experimental ani- 

 mals, unless submitted to great vascular pressure, coupled with 

 the principle submitted in the earlier chapters i.e., that ves- 

 sels supplied with a muscular coat are antagonistic to capil- 



