ORIGIN AND COURSE OF NER I r ES. 479 
adinaxillary glands (Klein) have been found, so far as they have been 
investigated, to be mucous glands. 
One or two points with regard to the structure of the alveolar cells, 
which bear upon questions we have to consider later, we may also 
mention. 
In all salivary alveolar cells there are found, though with very 
different degrees of distinctness, more or less spherical granules, destined 
in an altered or unaltered condition to become part of the secretion. 
Whether the cell substance, in which the granules are embedded, has 
or has not a definite structure, we cannot decide with certainty; this 
cell substance may be what we speak of as granular structureless 
protoplasm: or it may consist of two parts, — a protoplasmic part form- 
ing externally a boundary layer, except perhaps towards the lumen, 
and internally a delicate network ; and another part between the net- 
work and the granules, which in some cells may be of an albuminous 
and in others of a mucous nature. 
Every gland has its own distinctive histological features, implying a 
distinctive chemical character in the substance it secretes. In addition, 
secreting cells of obviously different nature often occur in the same gland. 
Thus, in the submaxillary gland of the rat, there is an ordinary albuminous 
portion, and running through this are tubes, in bold curves, consisting of cells 
with large granules, which sometimes leave an outer clear zone. And in the 
submaxillary gland of the rabbit, the first cells of the alveoli, and the terminal 
ductules, have in the fresh state conspicuous granules, differing widely from 
the faint granules of the rest of the cells in the alveoli. 
Origin and Coukse of the Xeryes to the Salivary Glands. 
All the salivary glands are supplied with nerve-fibres from two 
sources. They receive nerve-fibres, on the one hand, from the medulla 
oblongata, by way of some cranial nerve ; and, on the other hand, from 
the spinal cord, by way of the cervical sympathetic. 
The cranial nerve contains many, the sympathetic nerve comparat- 
ively few, secretory fibres. The cranial nerve contains vaso-dilator, 
and the sympathetic nerve contains vaso-constrictor fibres for the small 
arteries of the glands. There is, at present, no evidence worth con- 
sidering that the cranial nerves have vaso-constrictor fibres for the 
glands, or that the sympathetic nerve has vaso-dilator fibres for them. 
The chorda tympani and the nerve-cells with which it is 
connected. — The submaxillary, the sublingual glands, and the glands 
of the tongue, receive secretory and vaso-dilator fibres from the chorda 
tympani The chorda tympani arises from the seventh nerve: it leaves 
this in the Fallopian canal, runs across the tympanum, and joins the 
lingual branch of the third division of the fifth nerve. The nerve thus 
formed may be called the chordo-liTu/ual ; it extends roughly up to the 
dorsal edge of the sublingual gland ; here nearly all the fibres for the 
submaxillary gland, and about half of those for the sublingual gland, 
leave the lingual fibres, generally in four or five delicate strands, lying 
close together. These strands, with the tissue around thehi, are easily 
dissected out as a single bundle, and the bundle of nerve strands is 
called the chorda tympani, although it is a part only of the chorda 
tympani proper. The chorda tympani curves backwards towards the 
