906 THE EXTERNAL SECRETIONS 



especially concerned with a periodic renewal of the blood filling the 

 splenic spaces. 



The Tonsils. — The faucial tonsils consist of two globular masses 

 of lymphoid tissue placed in the recesses between the palatal arches. 

 Although originally developed in two lobes, an upper and a lower, this 

 demarcation disappears shortly before birth and the entire organ then 

 appears as a nearly spherical, slightly flattened disc which is attached 

 to the floor of the tonsillar sinus by a root consisting of tonsillar tissue 

 and a fibrous investment. The latter, in fact, spreads over its entire at- 

 tached surface and becomes continuous with the fibrous layer of the 

 neighboring mucous membrane. A number of membranous septa 

 extend from its surface into the substance of this organ, subdividing it 

 into a number of lobules. Its outer surface is covered with epithelium. 



The crypts of the tonsil may be single or branched. In the former 

 case, they retain a rather uniform diameter throughout their course, 

 while in the latter, their outer portions are much narrower than their 

 inner. They are directed, as a rule, in a straight line toward the sur- 

 face and show no contents with the exception of irregular accumula- 

 tions of cellular debris. Consequently, the capsule of the tonsil with 

 its trabeculse forms an inverted replica of the epithelium in which 

 are situated the blind ends of the crypts. A thin layer of lymphoid 

 tissue surrounds their basal portions, whence it extends outward and 

 divides the different crypts into several colonies.^ 



The Function of the Faucial Tonsils. — The tonsils reach their 

 highest development in the mammals in which they show a steady 

 growth early in life. They atrophy later on. Regarding their func- 

 tion we know little, the only definite conclusion beingthat they play the 

 part of a hematopoietic tissue. This inference seems justified in view 

 of their lymphoid structure. Many of the lymphocytes produced in 

 the germinal centers of their follicles find their way through the epithe- 

 lium into the crypts, where they help in the formation of the cheesy 

 masses so often found in these ducts. A certain number of them also 

 enter the general efferent lymphatics of the neck. It is a suggestive 

 fact that the tonsil attains is greatest activity during the early years 

 of life, when the body is still growing and is greatly in need of large 

 numbers of white corpuscles. It will be remembered that the other 

 lymphoid nodules are at this time similarly active. Consequently, the 

 tonsils merely participate in a general function and the part played 

 by them may readily be compensated for by other lymphoid tissues. 

 These facts tend to show that a mild degree of hypertrophy of the 

 tonsils is to be expected in early youth and that the removal of these 

 organs should not be advocated unless their size and condition leads 

 to such symptoms as impaired breathing, and an interference with the 

 voice and movability of the palate. 



The preceding deduction may be employed as a means of disposing 



1 Barnes, The Tonsils, Faucial, Lingual and Pharyngeal, St. Louis, 1914. 



