On the formation of the cryJlalUne humour oj the Eye, in various animals, 



birds, and fjhes. 



X HEcryftalline or tranfparent body or fubftaiice, (whicli is com- 

 monly called the cryflalline humour) of the Eye, is, inconfiftence or 

 liardnels, almoftthe fame as a preferved nutmeg. "When I firfl began 

 to make my obfervations on it, I cut off, with a Iharp razor, fome fmall 

 pieces or flices, and found it to confift of a fort of fcaly particles, laid 

 one on another, in a kind of circular form, taking their origin from 

 the center, and all of them then feemed to me, to be compofed of 

 cryflalline globules. After I had left this cryflalline fubdance, for 

 the fpace of three days to dry, it became fo hard, that it flew into 

 pieces before the edge of the knife, after the manner of rofin. 

 Upon again examining its nature and compofition, I perceived, not 

 only the fcaly formation, and intheeiculardireftion I have mentioned, 

 but I difcovered, that each of the fcales or coats was compofed of 

 parts, lying in a circular pofition, and in regular order, in rcfpe61: to 

 each other. In other words, the formation of the cryflalline iui- 

 mour, may be compared to a fmall globe, or fphere, made up of 

 thin pieces of paper, laid one on another : this will ferve to give an 

 idea of the fcales or coats above mentioned, and, fuppofmg each 

 paper to be compofed of particles or lines, placed fomewhat in the 

 jiofition of the meridian lines on a globe, extending from one pole 

 to the other, this may explain the nature of the conjponent parts of 

 thofe fcales or coats. 



Alter ^thefe firfl obfervations, I cin ployed inyfelf, more narrowly 

 to examine, the eyes of oxen and cows; for, I thought, that I had 



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