LIQUORS OF THE EYE. 513 



eye. Soon after, Mr Nicolas made a set of experiments on the 

 eyes of sheep and oxen, and announced the presence of phos- 

 phate of lime in all the humours, though Chenevix had not been 

 able to detect any.* In 1808, Berzelius published the second 

 volume of his Animal Chemistry, in which he gave an account 

 of a set of experiments which he had made to determine the che- 

 mical constitution of these humours.f The same experiments were 

 republished in the General Views of the Composition of Animal 

 Substances, published in English in 18134 He was equally un- 

 successful with Chenevix in his attempts to detect the presence 

 of phosphate of lime in these humours. 

 I. Eye of the sheep. 



1. The aqueous humour of the eye of the sheep is a clear and 

 transparent liquid like water, having (while fresh) very little 

 taste or smell. Its specific gravity at 60 is 1-0090, as determined 

 by Chenevix. Nicolas rates it as low as 1-C009. 



It scarcely alters vegetable blues while fresh, but when kept, 

 ammonia is generated, which gives it an alkaline reaction. 

 When heated to the boiling temperature, a very slight coagulum 

 appears. Chenevix says that when evaporated to dryness, it 

 leaves a residuum weighing not more than eight per cent of the 

 original liquid. But there must be a mistake in the statement, 

 as no other experimenter has obtained a residue weighing so much 

 as 2 per cent. Tincture of nut-galls occasions a precipitate both 

 before and after it has been boiled. From this Chenevix infers 

 that the aqueous humour contains gelatin. But it is more pro- 

 bable that the precipitate by tannin after boiling proceeds from 

 a residue of albumen which had not been thrown down by boil- 

 ing. Nitrate of silver detects in this liquor the presence of chlo- 

 rine. Acetate of lead throws down a white matter, but no pre- 

 cipitate is produced by any other metallic salt. 



The constituents of the aqueous humour of the sheep's eye, ac- 

 cording to Berzelius, are 



Water, . . . 98-10 



Albumen, . . . trace. 



Chlorides and lactates, . . 115 



Soda with animal matter soluble only in water, 0-75 



100- 



* Ann. de Chim. liii. 307. f Djurkemie, ii. 206. 



$ Annals of Philosophy, ii. 385. 



K k 



