202 
Dr. Hosacks Observations on Vision. 
“ inner angle ; so that the posterior are placed opposite to the 
“ middle of the interstices of the anterior, and planes passing 
« through each of the six, and through the axis, would mark 
“ on either surface six regular equidistant rays. 1 he muscu- 
“ lar fibres arise from both sides of each tendon, they diverge 
« t qi they reach the greatest circumference of the coat, and 
« having passed it, they again converge till they are attached 
« respectively to the sides of the nearest tendons of the oppo- 
“ site surface. The exterior or posterior portion of the six, 
“ viewed together, exhibits the appearance of three penm- 
“ formi-radiated muscles/' 
In the first place, to say nothing of the transparency of 
muscles, as an argument against their existence, we must un- 
avoidably suppose, as they have membranous tendons, which 
Mr. Young informs us he distinctly observed, that these 
tendons cannot possess the same degree of transparency and 
density with the bellies of these muscles ; that is, they must 
possess some degree of opacity, or certainly he could not have 
pointed out their membranous structure, nor even the tendon 
itself, as distinct from the body of the muscle ; and if they 
have not the same density, from their situation, and being of 
a penniform shape, must there not be some irregularity from 
the difference in the refraction of those rays which pass 
through the bellies of those muscles, and those again which 
pass through their membranous tendons ? Tnis structure then, 
of consequence, cannot be well adapted for a body whose re- 
gular shape and transparency are of so much consequence. 
Again, Mr. Young describes six muscles in each layer ; 
but Leeuwenhoek, whose authority he admits as accurate, 
relative to the muscularity of the lens, is certainly more to be 
attended to in his observation of bodies less minute, viz. as to 
