EPITHELIAL TISSUES. 22 
The majority of multicellular glands conform to one of two 
types, namely, the tubular gland, in which the secreting portions are 
of uniform calibre, and the acinous or alveolar gland, in which the 
secreting portions are sacculated (Fig. 3, A). Both types occur in 
simple, little branched and greatly branched conditions (Figs. 3, B, 4). 
Cutaneous glands of two types are cqgqmmonly present in 
mammals in association with the hairs, namely, sudoriferous or 
sweat-glands, which are glands of the tubular type, and sebaceous 
glands, which are of the acinous type. In the rabbit, glands are 
absent from the general surface, but are found in special situations, 
as, for example, in connection with the hair follicles of the lips, 
the internal surface of the ear, and the 
external genital organs. The inguinal 
- glands comprise both tubular and acinous 
portions. The mammary glands of the 
female are greatly modified cutaneous 
glands of an acinous type. 
Apart from the mucus-secreting cells of 
the general epithelium, the glands of the 
alimentary canal comprise the important Fic. 4.. From a section of 
the parotid salivary gland of 
but less elaborated glands of the wall,such — therabbit. A. Duct system in 
relation to body of gland: g, 
as the gastric glands of the wall of the acini of gland body; d, inter- 
lobular duct; B. Three indivi- 
stomach; and the greatly elaborated, out-  dualacini, highly magnified. 
standing glands which lie beyond the wall 
and are connected with the interior of the canal only through their 
ducts. The latter comprise the oral glands, the liver, and the 
pancreas. The oral glands include chiefly the submaxillary, 
parotid, sublingual, and infraorbital glands—conspicuous 
structures in the dissection of the surrounding portions of the head 
and neck. Their ducts communicate with the cavity of the mouth. 
The secretion of the oral glands has important mechanical 

functions in moistening the comminuted food in preparation for 
swallowing. It also contains ferments or enzymes, chiefly 
ptyalin, which is capable of transforming starch in soluble materials, 
though the digestive action is probably not exercised to a great 
extent. Pancreatic secretion, on the other hand, has little or no 
mechanical action, but its enzymes are of the greatest importance 
in digestion. 
