144 



OF FOOD, AND THE DIGESTIVE PROCESS. 



cells, which they believe to be the origin or ultimate termination of the Sali- 

 vary ducts. 1 The follicles are surrounded by a rich plexus of bloodvessels, 

 the interstices of which form spaces from which the lymphatics take origin 

 (Gianuuzzi). Pfltiger believes he has been able to follow nerve-fibres into 

 direct continuity with the cells lining the acini and ducts of the salivary 

 glands, and describes no less than four modes of termination. In the first 

 (1 and 2, Fig. 62), a cerebro-spinal nerve-fibre loses its sheath as it passes 

 through the basement-membrane of the acinus, with which the sheath be- 

 comes continuous, whilst the medulla passes on between the gland-cells and 

 divides into finer fibres, each of which, regaining a sheath, perforates the 



Fir,. f,2. 



3 



Modes of Termination of the Nerves in the Salivary Glands. 1 and 2, branching of the nerves be- 

 tween the salivary cells; 3, termination of the nerve in the nucleus ; 4, union of a ganglion cell with 

 a salivary cell; 5, varicose nerve-fibres entering the cylindrical cells of the excretory ducts. 



wall of one of the secreting cells, and terminates in the nucleus. In the 

 second mode (4, Fig. 62), the nerve-fibres, which probably belong to the 

 sympathetic system, terminate in multipolar ganglion cells, some of the offsets 

 or caudate prolongations of which in like manner penetrate the secreting 

 cells, and terminate in the nuclei. In the third mode (3, Fig. 62), a nerve- 

 fibre, invested with a sheath containing nuclei, within which are numerous 

 varicose axis cylinders covered by a thin layer of medullary substance, ter- 

 minates periphically in a conical enlargement, which he terms a " proto- 

 plasma-foot or expansion," and which he regards as a kind of intermediate 

 organ between the nervous and glandular substance. Lastly, he has ob- 

 served certain nerve-fibres distributed to the cylindrical cells lining the sali- 

 vary ducts (5, Fig. 62). The attached extremity of these cells is often 

 marked with longitudinal stride, and is continued for some distance as a vari- 

 cose prolongation. The nerve-fibres lie beneath the basement-membrane, 



1 Boll has described an intra-alveolar reticulum of connective tissue which is per- 

 haps identical with it. 



2 Pamphlet, On the Terminations of the Secretory Nerves of the Salivary Glands, 

 1866; and Mediein. Centralblatt Nos. 10 and 14,1860; see also Palladino (Abstract 

 in Centralblatt, 1873, p. 782), who, however, was only able to trace ?ion-niodullated 

 nerve-fibres into the secretory cells of the submaxillary gland in the Horse. Asp 

 (Abstract in Centralblatt, 1873, p. 565), Mayer, Hering', Krause, Schweigger-Seidel, 

 Henle, Klein, Ewald, and many others, express grave doubts as to the accuracy of 

 Pfliun-r's statements of the mode of termination of the nerves in the salivary glands, 

 and the subject may be regarded as being still sub judice. 



