44 
clearer blue. Sulphite of soda has no effect on an acid solu- 
tion, and, therefore, the colour is C al t (4) . I have not yet 
met with this in any other substance, and it is interesting as 
being one of the very few blue colours soluble in water or 
alcohol which belong to my group C. These are as follows : 
Phyco-cyan 1 C aq* (2-f- 4|) 
Blue colour from the 
flowers of Salvia patens 
Aniline blue C alj (3-i-). 
When the alcoholic solution of the blue of the wood is 
diluted with water and agitated with ether it is precipitated 
from the solution, and collects at the line of junction of the 
water and supernatant ether ; but when agitated with ben- 
zole this liquid rises to the top coloured blue. The solution 
may, however, be obtained in a more simple manner by 
digesting the wood in benzole, which dissolves more colour 
than alcohol, and it is of a fine green-blue tinge. The spec- 
trum is the same as that of the alcoholic solution ; but both 
of these fade in the course of a few days, even when sealed 
up in glass tubes, so that neither can be kept as a permanent 
object. 
jC aq Q (4 H) 
On the Epithelium of the Cornea of the Ox. By John 
Cleland, M.D., Professor of Anatomy and Physiology, 
Galway. 
(From the ‘ Journal of Anatomy and Physiology,’ new series, No. i.) 
It is well known that there are many appearances in 
stratified epithelia not easily explained by that simplest 
theory of their growth which is naturally first suggested, and 
is no doubt in all instances partially true ; namely, that cells 
originating in a deep position pass gradually to the surface 
as they grow and alter in figure, while those superficial to 
them are cast or dissolved, and others behind them follow in 
their steps. Thus the elliptic cells in the deeper strata of 
the epithelium of the trachea can scarcely be supposed to be 
developed into the ciliated columns which lie over them ; and 
it cannot be imagined that in the ureter the large and irre- 
gularly shaped cells are altered so as to form the smaller and 
flatter cells found on the surface. 
1 Cohn, ‘ Arcliiv. fur Microskopische Anatomic,’ 1807. 
