36 PROGRESS OF VETERINARY SCIENCE AND ART. 
ranula. Ranula, as Erichsen describes it in his f Science 
and Art of Surgery/ is a globular swelling, semitransparent, 
evidently containing fluid, and often attaining the size of a 
walnut or pigeon’s egg, situated under the tongue, pushing 
this organ upwards and backwards, and consequently inter- 
fering with deglutition and speech. The walls of the cyst 
are usually thin, with small vessels ramifying on them ; its 
contents are watery and serous. Sometimes albuminous , and 
occasionally cretaceous matters are found intermixed, in some 
instances even in large quantity, as much as half a pound 
of plastery stuff’ having been met with in a cyst of this 
kind.” Ranula in man was looked upon simply as a tumour, 
till Wharton described the duct of the submaxillary gland, 
when it was said that in ranula there was obstruction and 
dilatation of this duct ; but Bernard says such is not the case, 
and that probably it consists in a dilatation of the small 
ducts of the sublingual glands. Bernard has observed a case 
of obstruction of these ducts in the horse, with formation 
of a cyst containing a fluid analogous to that seen in 
ranula. The contents of such cysts have a close analogy 
with the sublingual saliva, but from being viscid and gluti- 
nous, it may become purulent in consequence of inflamma- 
tion of the parietes of the cyst. 
Sublingual Glands. — The existence of these glands in 
certain animals has been denied by some anatomists, but they 
are as constant as the function with which it is related. It has 
likewise been said that they may be blended together with 
the submaxillary glands, but Bernard says they are always 
distinct. 
The sublingual saliva is distinguished from that of the 
other glands by its greater viscosity. It is transparent and 
there is no deposit of salts on cooling. It is alkaline, but 
there is no sensible effervescence on the addition of acids to 
it. It is characterised by the great proportion of ptyalin. 
It does not coagulate by heat, and is not precipitated by 
any metallic salt. Water containing sublingual saliva dis- 
solves saline substances with difficulty. 
The three kinds of saliva differ from each other in the 
nature of their organic elements : 1st. The parotidean saliva 
is watery, and contains a great quantity of a substance re- 
sembling albumen. 2d. The sublingual contains a viscid 
matter which does not acquire greater density on cooling. 
3d. The submaxillary is characterised by a viscid material 
which gelatinizes on cooling. 
21, Dublin Street, Edinburgh; Bee., 1856. 
( To be continued .) 
