Dr . Hosack's Observations on Vision. 
it more or less convex ;* others, that it removed it nearer to 
the cornea ;f and others, that it removed it nearer the retina. J 
The advocates for these different opinions all agree in at- 
tributing these effects to a supposed muscularity of the ciliary 
processes. 
Of the structure of these processes Haller observes, “ In 
“ omni certe animaliutn genere processus ciliares absque ulla 
“ musculosa sunt fabrica, mere vasculosi vasculis serpentinis 
“ percursi molli facti membrana/' Which structure, I be- 
lieve, at present is universally admitted. But even supposing 
them muscular, such is their delicacy of structure, their at- 
tachment, and direction, that we cannot possibly conceive 
them adequate to the effects ascribed to them. Beside, what 
we observed of the muscles of the lens itself, also applies to 
the processes, viz. that they may be destroyed, as in couching 
or extraction, and yet the eye be capable of adapting itself to 
the different distances of objects. For a more full refutation 
of these opinions, see Haller's large work. 
The Situation, Structure , and Action of the external Muscles ,§ 
Upon carefully removing the eyelids, with their muscles, we 
are presented with the muscles of the eye itself, which are six 
in number ; four called recti, or straight ; and two oblique ; 
* Des Cartes, Scheinerus, Bidious, Molli nettus, Sanctorius, Jurin. 
f Kepler, Zinn, Porterfield. 
t La Chariere, Perrault, Hartsoeker, Brisseau, and Derham. 
$ For the accuracy of the representation I have annexed (in Tab. XVIII. ) I can vouch, 
having been at much pains in the dissection ; from which I had the painting taken by 
a most accurate hand, Mr. S. Edwards, a gentleman well known for his abilities in 
ihe plates of that admirable work, the Flora Londinensis. 
