HOBGKIN'S DISEASE 377 



The same is true of the third previously mentioned form of glandular 

 enlargement, lympho-sarcomatosis. According to Virchow, a hard and a soft 

 form of lympho-sarcoma have been differentiated, depending upon whether or 

 not the proliferation of the reticulum of the gland and of the connective tissue 

 predominates over the cell proliferation. The softer forms, however, show 

 gradual transition stages to the pure lymphomata or lymphadenomata, so that 

 even for the pathologist the decision between these varieties of tumors may 

 be very difficult. Hence, the harder composition of the lymphosarcomata, com- 

 pared to the lymphomata, has very little diagnostic importance, as the differ- 

 ence is not decisive. Somewhat more valuable in diagnosis is the fact that 

 lymphosarcoma has a greater tendency to invade the capsule of the gland 

 and the neighboring tissue, and to rupture through the skin, which never 

 occurs in pure lymphomata, but which does occur, as has just been stated, 

 in tubercular adenitis. The tendency to metastasis, which has been mentioned 

 as characteristic of lymphosarcoma, is of very slight value in diagnosis during 

 life, for three reasons : First, adenitis of other types readily causes metastases 

 in internal organs, either by way of the lymph stream or blood channel; sec- 

 ondly, metastases are frequently not recognizable by symptoms; and thirdly, 

 in the presence of certain symptoms it may be difficult, even impossible, to 

 decide whether these symptoms are due to actual metastatic tumors in an 

 organ or are only caused by the pressure and irritation which glandular tumors 

 in the cavities of the body exert upon a neighboring organ. Thus, for exam- 

 ple, symptoms which point to an affection of the respiratory apparatus, dysp- 

 nea, cough, etc., may be caused by metastases in the lungs or in the bronchi, 

 as well as by pressure of enlarged mediastinal glands. 



To all this we must add that, even in quite unquestionable cases of lympho- 

 sarcoma, we find the blood-picture which Ehrlieh and Pinkus have designated 

 as characteristic of pseudo-leukemia produced by multiple lymphomata. 



It will, therefore, not be looked upon as an exaggeration when I say that 

 only in a small minority of cases is it possible to recognize with certainty the 

 anatomical nature of the glandular enlargements which are the foundation of 

 the clinical picture of pseudo-leukemia. [See note on page 371. — Ed.] 



ETIOLOGY 



As to etiology very little has been determined with certainty. The affec- 

 tion appears in childhood and in adolescence, somewhat more frequently in 

 the male than in the female sex. Occasionally several cases have been noted in 

 the same family, for instance, among brothers and sisters or in one of the 

 parents and a child, and this suggests a hereditary or family predisposition. 



Not infrequently pseudo-leukemia occurs in connection with other dis- 

 eases as, for example, malaria, and often in my experience, after diseases which 

 are combined with an inflammatory irritation of the nasal cavities and of the 

 tracheo-hronchial m,ucous memlrane, i. e., after inflammations of the throat, 

 measles, whooping-cough, influenza and the like. One might assume that 

 from the areas of mucous membrane just mentioned an irritation is exerted 

 upon the glands which causes enlargement, but then it remains unexplained 



