Addison, on Blood-corpuscles. 21 



to float out in tlie two fluids, we find them experiencing further, 

 but different, changes of form. In the alkaline fluid the phases 

 A, B, fig. 2, and in the acid fluid the phases c, d, e, fig. 3, 

 will be seen. Again, take a small drop of blood and place 

 close to it an equal quantity of the alkaline-saline liquid, 

 drop down upon them a thin piece of glass, and when a mul- 

 titude of the corpuscles have floated out into the fluid and 

 have assumed forms fig. 2, add at an edge of the covering- 

 glass a drop of the diluted hydrochloric acid, and these forms 

 will be seen changing into the forms fig. 3. Lastly, take a 

 drop of blood and place near to it an equal amount of the 

 acid-sugar solution, let fall upon them a thin covering-glass, 

 and after a little time numerous corpuscles will be found of 

 the forms represented fig. 3, add at an edge of the covering- 

 glass a drop of liquor potasses, and forms fig. 3 will alter into 

 forms fig. 2. The changes described may take place quickly 

 or more slowly, according as the added fluid flows with more 

 or less rapidity ; in the latter case it will be remarked that 

 the corpuscles in progress of change from one form to the 

 other regain for a brief space of time their normal figure and 

 appearance (fig. 1) . We are able, then, by an appropriate appli- 

 cation of alkaline and acid fluids to impress particular forms 

 upon the red corpuscles of human blood, and we see them 

 during the transition from one form to another regain their 

 normal characters and aspect. 



This property of change of form in the corpuscles of the 

 blood is not of long duration, it remains with them but for a 

 limited period after their withdrawal from the circulation, 

 and some of the corpuscles appear to lose it sooner than 

 others, for, after a little time, corpuscles of diflierent forms 

 are to be seen floating side by side in the same current, 

 and the further addition of an alkaline or acid fluid destroys 

 them, without inducing any further change of figure. 



We have called forms fig. 2 alkaline, and forms fig. 3 

 acid forms, not because they are exclusively determined in 

 the one case by alkaline and in the other by acid liquids, 

 but because the alkali potash will change the normal form 

 fig. 1, and also forms fig. 3, into the forms fig. 2, and, again, 

 because the hydrochloric and other acids will alter the nor- 

 mal form, and also the forms fig. 2, into forms fig. 3, when 

 they are properly applied. 



In repeating these experiments, it will be seen that cor- 

 puscles which approach near to an edge of the covering-glass, 

 whatever may be their form, lose thereby all power of fur- 

 ther change. 



Now forms b, fig. 2, which result from contact with alka- 



