262 LECTURE XI. 



A. third series of conditions may here too be men- 

 tioned, which, however, do not affect the form of the 

 blood-corpuscles, that, namely, in which the internal con- 

 stitution of these elements has undergone changes, with- 

 out the production of any definite morphological effect. 

 Here we have essentially to deal with functional disturb- 

 ances which are probably connected with more subtle 

 changes in the composition of the blood, changes in the 

 proper respiratory substance (respiratorische Substanz). 

 For just as in muscles we find the substance of the pri- 

 mitive fasciculus, the compact mass of syntonine, to be 

 the contractile substance, so in the contents of the red 

 corpuscles do we recognize the presence of the really 

 active, respiratory substance. This under certain cir- 

 cumstances undergoes changes which render it incapable 

 of continuing its functions, a kind of paralysis, if you 

 will. That something of the kind has occurred we see 

 from the fact that the corpuscles are no longer capable 

 of absorbing oxygen, as may be directly proved by expe- 

 riment. That molecular changes in the composition of 

 the blood are here really at work, we find satisfactory 

 evidence in the action of poisonous substances which, 

 even in extremely minute quantity, so change the hsema- 

 tine that it is thrown into a kind of paralysis. To these 

 substances belong a part of the volatile compounds of 

 hydrogen, for example, arseniuretted and cyanuretted 

 hydrogen, and further, according to Hoppe's investiga- 

 tions, carbonic oxide, of all of which comparatively very 

 small quantities are sufficient to diminish the respiratory 

 power of the corpuscles. Analogous conditions have 

 already long since been observed by many in the course 

 of typhoid fevers, in which the capability of taking up 

 oxygen decreases in proportion as the disease assumes a 

 severe and acute character. Microscopically, however, 

 with the exception of a few melanic corpuscles, scarcely 



