EFFECTS OF FLUIDS UPON THE RED CORPUSCLES. 173 



ing which perhaps one or more other matters pass out, 

 as, for example, salt, but the essential constituents 

 remain behind. The hsematine does not follow the 

 water ; the membrane of the blood-corpuscles keeps it 

 back, so that when a large quantity of fluid is lost, the 

 hsematine in the interior must of course become propor- 

 tionately increased in density. 



The reverse is the case when we employ diluted fluids. 

 The more diluted the fluid, the more does the blood-cor- 

 puscles enlarge ; it swells up and becomes paler. On 

 treating blood-corpuscles, which have become smaller 

 from the action of concentrated fluids, with water, we 

 see them pass back from the globular into the angular 

 form, and from this into the discoidal one ; after which 

 they continually become more and more globular, often 

 assume very peculiar shapes, and again grow paler. 

 This process may, if the dilution of the blood be effected 

 with great precaution, be continued until the blood-cor- 

 puscles scarcely seem to retain a trace of colour, though 

 they still remain visible. In ordinary cases, when much 

 liquid is added at once, such a violent revolution is pro- 

 duced in the economy of the blood-corpuscle, that an 

 escape of the haematine immediately ensues. We then 

 obtain a red solution, in which the colouring matter is 

 free and dissolved in the fluid. I call your attention to 

 this peculiarity, because it is continually occurring in the 

 course of investigations, and because it explains one of 

 the most important phenomena in the formation of 

 pathological deposits of pigment, in which we meet with 

 a precisely similar escape of haematine from the blood- 

 corpuscles (Fig. 54, a). The expression generally made 

 use of under such circumstances is, that the blood- 

 corpuscles are dissolved, but it has long been a well- 

 known fact that, as was first shown by Carl Heinrich 

 Schultz, although there apparently no longer exist any 



