66 POPULAR SCIENCE MONTHLY. 



These phenomena are above all visual, and the intellectual character 

 of mescal intoxication as compared with perhaps any other intoxication, 

 seems connected with the fact that it is the most intellectual of the 

 senses that is chiefly involved. The visual effects of mescal may be of 

 very various character, largely depending on the idiosyncrasy of the 

 subject as well as on the degree of the intoxication. They vary from 

 an exaggeration of the normal phenomena, producing a heightened play 

 of light and shade and color, to visions seen on the curtain of the eye- 

 lid with closed eyes and with open eyes in the dark, up to actual localized 

 hallucinations seen in broad daylight. It seems reasonable to suppose 

 that the cerebral centers of vision are affected under mescal, and the 

 occipital headache which occasionally follows supports such an assump- 

 tion; a merely peripheral stimulation could scarcely suffice to account 

 for such an crgy of vision. But at the same time I am convinced that 

 the conditions produced in the eye itself are important factors in the 

 production of the phenomena. Not only must we suppose that the 

 retina, like all the sensory apparatus, has become hyperaesthetic, but the 

 pupils are dilated, so widely dilated in one of my subjects that there 

 was extreme photophobia. It is probably not without significance that 

 in the other chief vision-producing drugs, such as haschisch and bella- 

 donna, the pupils are also dilated. It is evident that light can penetrate 

 into the chamber of the eye with much more ease than usual. The 

 Kiowa Indians sit round a fire during the nights on which the mescal 

 rites are performed and I have found that the flicker of fire-light acting 

 through the closed eyelids furnishes a very favorable condition for 

 seeing the visions to advantage. 



There is another characteristic of a large number of these visions 

 (as indeed of many visions otherwise produced) which, it would seem, 

 we must explain through peculiarities of the eye. I refer to what I have 

 termed their kaleidoscopic character, the tendency to symmetrical group- 

 ing in the visual field of objects similar in shape, and harmonious, 

 though not necessarily similar, in color, so that a kind of vision is pro- 

 duced such as we might attribute to an animal with faceted eyes. We 

 might account for such a phenomenon by means of that irregular 

 astigmatism, found more or less in normal eyes, which has been 

 attributed to the fact that the crystalline lens is composed of many 

 sections connected by radial sutures, or, more plausibly, with Shelford 

 Bi dwell, who has made some interesting experiments on this point, to 

 the light passing through the coarse-meshed tissues of the eyes.* With 

 perhaps still greater probability we might adopt the suggestion of Zehen- 

 derf who in dealing with subjective visual perceptions would explain 

 the strikingly regular polygonal figures which arise under various con- 



* Shelford Bidwell, ' Multiple Vision,' Nature, April 13, 1899. 

 t Klinische Monatsilatt fur Augenheilkunde, November, 1895. 



