282 DIGESTIVE ORGANS. [sect. 1 34. 



small vessels, which penetrate, with the excretory ducts, or inde- 

 pendently, between the lobules, and form in the interior a wide 

 network of capillaries, 0-003'" in diameter, surrounding the indi- 

 vidual tubes and vesicles ; so that, in every case, each of them is in 

 contact with three to four capillaries. Nerves are met with in 

 considerable abundance upon the excretory ducts, and occasionally, 

 also, as moderately fine fibres, in the glands themselves. 



The secretion of the racemose glands is a clear yellowish mucus, 

 obviously coming from the epithelial cells, mingled accidentally with 

 granules, nuclei, and remains of cells. It fills the excretory ducts 

 and the other glandular spaces as far as the ultimate terminations, 

 and even in these can be brought to view, on the addition of acetic 

 acid, as a striated viscid substance. Mucous corpuscles, as they 

 are termed, such as are found in the fluids of the mouth, are 

 totally absent in the glands. 



2.— FOLLICULAR GLANDS. 



§ 134. The follicular glands of the oral cavity are 1, simple fol- 

 licles at the root of the tongue ; and 2, compound, on either side 

 of the isthmus faucium, viz., the tonsils. In structure, these organs, 

 whether simple or compound, are essentially alike, inasmuch as 

 the tonsils may be regarded as being made up of simple follicular 

 glands; on the other hand, they differ so widely from the mucous 

 glands, that they cannot be ranked with tliem in any respect. 



The simple follicular glands of the root of the tongue, extending as 

 an almost continuous layer from the papillee vallatce to the epiglottis, 

 and from one tonsil to the other, lie above the mucous glands 

 of this region and immediately beneath the mucous membrane. 

 Their position is so superficial, that the individual glands can be 

 perceived as rounded elevations, and their number and arrange- 

 ment recognised externally. On being dissected out, each follicle 

 is found to be a lenticular or spherical body, of V" to 2'" in dia- 

 meter, which, covered externally by the mucous membrane — here 

 very thin — is loosely imbedded in the submucous tissue, and re- 

 ceives, at its lower surface, the excretory duct of a more deeply 

 seated mucous gland. Every follicular gland presents in the 

 centre of its free surface a punctiform opening, often rather wide 

 (i'" to V"), and readily visible to the naked eye, which leads into 

 an inverted-funnel-shaped cavity, characterised by its narrowness 

 compared with the size of the follicle, and by its thick walls. The 

 cavity is generally filled with a greyish mucous substance. 



