"EYES AND SCALES OP FTSHES. 383 



With regard to the little effect which ardent spirit produces 

 on the spicula, it may be remarked, that scarabsei, and other 

 coleopterous insects, often remain a considerable time immer- 

 sed in spirits before they become motionless, and, when taken 

 out after a lapse of four or five hours, frequently recover. 



Fifth, Are not these spicula formed and nourished by blood- 

 vessels as the other parts of the fish are ; and, if so, how can 

 they be considered as distinct animals? This question, it must 

 be confessed, is almost unanswerable. To prove that vessels 

 cannot be traced into them, would be to prove nothing ; for in 

 many parts of the body, as the cartilages of the joints, ves- 

 sels cannot, even by the finest injections, be detected. The 

 spicula are chiefly abundant in the cellular substance which 

 connects the outer layer of the choroid to the sclerotica, and 

 there they seem to have little or no adhesion, at least not more 

 than would seem to arise from their confinement amona- cellu- 

 lar substance. Hence, in merely separating the choroid from 

 the sclerotica, they are obtained in thousands. When the 

 choroid also is dissected off, and gently shaken in a phial with a 

 little watei', the liquid very soon becomes milky, from their 

 dispersion through it. 



This looseness, or want of connection, is, h^ever, of little 

 consequence with respect to the present argument, since the 

 brain or the pulpy retina may be diffused through water with 

 almost as much ease, yet both are perfectly vascular. The 

 particles, however, into which the brain or retina is broken are 

 quite irregular, and of different sizes or clusters, and of pulpy 

 consistence, and exhibit no appearance of motion. The spi- 

 cula, on the other hand, seem to be rigid, are always distinct, 

 and of a constant determinate form, and keep up a perpetual 

 motion and reflection of light. 



3 C 2 Perhaps 



