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IV. — Miscellaneous Observations on the Blood. By John Davy, M.D., F.R.S., 



Lond. & Ed., &c. 



(Read 6th March 1S65.) 



On a fluid of so much importance as the blood, observations with any preten- 

 sion to accuracy can hardly be too often made and repeated, more especially 

 when we consider its great instability, its little uniformity, and the differences 

 of opinion entertained by physiologists respecting some of its most remarkable 

 properties. 



Such is the persuasion which has influenced me in engaging in the present 

 inquiry, and in submitting its results to the Society. 



I. On the Action of Water on the Red Corpuscles of the Blood. 



As is well known, the red corpuscles are altered in form and appearance on 

 admixture with water, the most obvious change being, that from discs they 

 expand into globules. 



In some trials made with the view to ascertain something more precise, I have 

 selected the blood of birds, that chiefly of the common fowl and duck, the cor- 

 puscles of their blood, from their elliptical shape, being peculiarly fit, as it seemed, 

 for the inquiry. 



The first trials made were to ascertain the proportion of water that was 

 required to effect any material change. The results obtained were the follow- 

 ing :— 



When one measure of water was added to one of serum holding red corpuscles 

 in suspension, but few of them experienced an immediate change of form and 

 became globular. 



On the addition of two of water, the majority of the corpuscles underwent 

 this change, a few only retaining their normal form. 



On the addition of three of water, none of a normal form could any longer be 

 seen ; all that were visible were rounded, much reduced in apparent size, and were 

 much less distinct ; indeed, a nice adjustment was required to detect them. Many 

 of them had a jagged outline ; and from some there was a slight projection, sug- 

 gestive of a rupture of their capsule. 



Dried by evaporation at about 100° Fahr., very many of them were found to 

 have recovered their original form and size. Some of them, however, appeared 

 to be ruptured, the excluded nuclei adhering to their surface; others retained 

 their nuclei, of irregular appearance ; all appeared to be wasted. 



VOL. XXIV. PART I. F 



