Herrick, Pathology of General Paralysis. 147 



sparingly present in this case may be of the character of a dif- 

 fuse stroma. Ziegler says that the spider cells are frequently 

 not increased in number but simply more conspicuous because 

 of the atrophy of other parts of the cortex. The fact referred 

 to by Lewis that representativeness is a function early lost in 

 the course of general paralysis may have its anatomical explana- 

 tion in the fact that slight sporadic changes would interfere with 

 associational tracts (association being intimately connected with 

 representation) before becoming sufficiently pronounced to in- 

 terfere with the direct presentational processes of perception, 

 etc. In fact, according to Tuczek, there is a marked primary 

 atrophy ot the fine meduUated nerve fibres, particularly in the 

 outer layers of the cortex, in the tangential "associational" 

 fibres which run parallel to the surface. Friedmann describes 

 four varieties of atrophy of the white matter and others have dis- 

 covered secondary degeneration in the dorsal columns of the 

 the cord. Our methods were selected with reference to the 

 cells and, whether for this reason or because no genuine degen- 

 eration of the fibres had set in, only sparing and unimportant 

 degenerations of white matter were encountered. 



In determining the cause and nature of the circulatory 

 changes preceding cerebral degeneration a thorough knowledge 

 of the nature and reactions of the blood and lymph which fill 

 the delicate cerebral organ as fluid fills a sponge is necessary. 

 The brain is almost as really an erectile tissue as the pan- 

 creas and we already know enough to be convinced that slight 

 changes in pressure may become the occasion for the rapid pro- 

 liferation of the corpuscles and that the presence of small quan- 

 tities of certain substances may greatly change the balance of 

 the fluids in the capillaries, lymphatics and tissues. R. Heid- 

 enhain has conducted very elaborate investigations upon the 

 lymph^ and finds that there are lymphagogues or substances 

 which increase the formation of the lymph. Various extracts 

 of invertebrate muscles, ^^^ albumen, peptone, etc., are 



'Versuche und Fragen zur Lehreivon der Lymphbilding. PflUgers Archiv 

 f. d. ges. Physiologie XLIX, p. aog. 



