TYPHUS. 439 



to the local action of the typhoid poison, ioasmuch as they are 

 produced in those very organs which arc probabh', according to 

 recent investigations (enteric fever from drinking-water)^ the 

 channels through which the poison is introduced into the system. 

 § 377. Several stages have been distinguished in the course 

 of abdominal typhus ; the catarrhal stage, the stage of medullary' 

 infiltration, the stage of degeneration, and that of ulceration. 

 We will retain these divisions, premising however, that the 

 general catarrh of the alimentary tract which ushers in the pro- 

 cess, may continue, without undergoing any marked abatement, 

 until the final stage. Strictly therefore, the division into stages 

 is only applicable to the special alterations in the lymphatic 

 follicles, on which indeed the attention of the anatomist is con- 

 centrated from an early period. During the catarrhal stage, 

 (which seldom comes under observation), all the Peyer's patches,, 

 and the solitary follicles of the small and great intestine, become 

 swollen in the manner described in § 350. The greyish, pearly 

 nodule, surrounded by its close web of vessels, is the acme of the 

 process in this direction ; thereupon, the swelling for the most 

 part subsides entirely, particularly in the solitary glands ; here 

 and there, especially m Peyer's patches, the character of the 

 swelling undergoes a change, without the occurrence of suppura- 

 tion and expulsion of the follicles ; the latter passing into the 

 state of "medullary infiltration." 



This " medullary infiltration " is mamly distinguished, on the 

 one hand by an enlargement of the follicle, which may attain 

 even six times its normal size, on the other by an extension of the 

 morbid process to tlie perifollicidar connective tissue. The follicles 

 wliich make up a Peyer's patch, coalesce \^ith the interstitial con- 

 nective tissue to form a soft, rose-coloured, seemingly homoge- 

 neous mass, which closely resembles the medullary substance of 

 the foetal brain; the entire patch forms a flattened elevation, 

 about two lines in height, of an elongated oval outline; it is 

 marked ofP from the surrounding mucous membrane by a pre- 

 cipitous border. The solitary follicles are converted by the infil- 

 tration into marrowy nodules, from two to fom* lines in diameter ; 

 it is in these, that the extension of the morbid process to the 

 mucosa is most strikingly apparent ; since the greater part of the 

 nodule is obviously made up, not of the follicle itself, but of the 

 mucous membrane which covers it. 



