27 



The epidermoid lamina^ appears to be arranged Hive tlie slates or 

 shinorles on a liouse, one over-lapping another, as nnay be demonstrated 

 by raising their edges by the point ot" a lancet, and pulling them troni 

 their connections, as in micacious plates. Each lamina, though inappre. 

 ciably thin, is without doubt, an aggregation of other similar laminae. 



The superficial surface of one of these plates, is various and uncer- 

 tain, being sometimes nearly as broad as the human nail. A lamina 

 does not lie exactly horizontal, but dips or inclines slightly; its outer 

 terminal margin, being black, and possessing an absorptive power over 

 the spectrum, little inferior to charcoal itself. 



This laminated stratum, is opaque only to a very limited extent along 

 its margins, at which, will often be found, interspaces poysessing more or 

 less of that essential element of miscroscopic research, transparency. 

 The plate constantly becomes more pellucid towards its inner termina- 

 tion. 



The specimen here examined, \vas taken from a skin which had been 

 dried for many years, portions of which, were used in that state, as well 

 as after maceration from one day to six weeks. Maceration and tritu- 

 ration of the cuticle, with a suitable quantity of water, give a mixture, 

 which, to the naked eye resembles black vomit. 



The microscopic analysis of this substance when conducted in the 

 direct rays of the sun, presents, like all other substances, which I have 

 examined, (and they are not few,) certain ultimate phenomena, which 

 will be described presently. And, although, the alligator's scarf skin 

 is not a good type, or point of departure for the illustration of the gen- 

 eral doctrine — the germ of which, only, I wish here to delineate, still 

 it is sufficiently adapted to my purpose. Great as is my distrust, in my 

 abilities in this branch of science, I cannot persuade myself, that my 

 observations are mere optical illusions, or the figments of fancy — errone- 

 ous they may be. But as my method is, as I suppose, peculiar — the 

 solar microscope, so called, having nothing to do with it, and as it has 

 been practised at intervals for nearly tvro }'ears, it cannot be considered 

 altogether premature or hasty. Besides, I am far from thinking that my 

 observations conflict with the general laws of light and of optical in- 

 struments. 



An epidermic plate of the alligator, presents the three elements, which, 

 so tar as I have observed, constitute the structure of animals and plants, 

 both liquid and solid, upon examination, by what, I shall call solar ana- 

 lysis. It would be, I repeat, utterly impossible in this place to give 

 even an outline of the experimental proof, which I have accumulated in 

 less than two years, and which has induced me to draw this conclusion. 

 I cannot enter upon the objections which professed opticians, and mi- 

 croscopists may urge against a method, (I shall call it the solar method,) 

 which is universally interdicted, involving as they do, the protbundest 

 speculations concerning the refrangibility, the irisation,* the reflexion, 

 the absorption, the entrance, the transit, the emergence, the color, the 

 concentration — in a word, the general doctrines of light or the solar 



* Irisation. — Webster has not admitted this necessary word, though he has 

 irisated and irised. The dictionary of the French Academy, has tJie adjective 

 irise, (that which presents the color;? of the rainbow.) but not irimlion ! 



