CATARRH. 409 



<?xtenslve •implication o^ those lymphatic structures which are 

 traversed by the lymph returning from the affected membrane. 

 The first to become involved are the follicles embedded in the 

 substance of the mucous membrane : the lymphatic glands proper, 

 which lie outside the mucous tract, come next, and that in the 

 following order : in catarrh of the nasal, pharyngeal and buccal 

 cavities, the glands of the neck ; in catarrh of the respiratory 

 tract, the glands about the root of the lungs and the bifurcation 

 of the trachea ; in catarrh of the digestive tract, the mesenteric 

 glands ; in catarrh of the genito-urinary apparatus, the retro- 

 peritoneal and inguinal groups of glands. 



As regards the process itself, it is essentially a form of acute 

 suppurative lymphadenitis, described at length in § 200 et seqq. 

 Its simplest and least complicated manifestation is the follicular 

 siqypuration of the gasti'O- intestinal mucous nienihrane. The violent 

 catarrhal disorders of the intestine, which occur during the 

 height of summer, occasionally exhibit all stages of the process 

 at once ; its beginnings may also be studied as intercurrent or 

 prodromal phenomena in tuberculosis, enteric fever, Asiatic 

 cholera, and dysentery. The swelling usually begins with a 

 marked congestion of the perifollicular blood-vessels ; the 

 general hypera^mia seems to concentrate itself round the folhcles ; 

 this hyper89mia may be partly collateral, due to the impeded 

 access of blood to the follicle itself The solitary gland presents 

 itself as a dull-grey, pearly nodule, as large as a pin's head, sur- 

 rounded by a vascular ring. A Peyer's patch in this condition 

 is a most beautiful object ; the hypera^mic areola) of its con- 

 stituent follicles being in contact with one another. When sup- 

 puration occurs, the follicle swells to the size of a small pea ; its 

 site is indicated by a yellowish, fluctuating point, over which the 

 outer layer of the mucosa is moderately stretched. If the pus is 

 let out, the roof of the cavity falls in, and a slight hollow^ is left. 

 A stream of water distends the cavity once more, and enables us 

 to appreciate its striking dimensions. These can only be ac- 

 counted for by assuming that the perifollicular connective tissue 

 has become involved in the suppurative process. For, so long 

 as the pus remains enclosed in the parenchyma of the mucous 

 membrane, it exerts — if I may be allowed the comparison — a 

 catalytic action upon the connective tissue which immediately 

 surrounds it. Hence we not unfrequently find the contiguous 



