1 34 Dr. Hodgkin and,!. J. Lister's Microscopical Observations 



less central globules which have been strongly insisted on by 

 Sir Everard Home and Bauer, and by Prevost and Dumas, 

 and which have been regarded not merely by themselves, but 

 by other distinguished, and intelligent physiologists, as con- 

 stituting by their varied combination the different organic tis- 

 sues. The separation and detection of these globules is stated 

 to be facilitated by some of the means which effect the changes 

 to which I have alluded ; but, as I have already stated, we have 

 in vain looked for these globules. 



After blood taken from the living body has been kept a suf- 

 ficient length of time for an alteration in the form of the par- 

 ticles to commence, and this according to circumstances will 

 be from a very few hours to one or more days, the first change 

 which we have noticed is a notched or jagged appearance of 

 the edge of a few of the particles. The number so modified 

 continues to increase : some of the pai-f icles lose their flattened 

 form, and appear to be contracted into a more compact figure ; 

 but their outline continues to appear irregular and notched, 

 and their surfaces seem mammillated. Hewson and Falconar 

 appear to have accurately noticed this change, and have com- 

 pared tiie particles in this state to little mulberries. When 

 more time has elapsed, most of the particles lose this irregu- 

 larity of surface and assume a more or less perfectly globular 

 form, and reflect the image of an interposed opaque body as 

 a convex lens would do. Some of the particles resist these 

 changes much more obstinately than others. 



If a small quantity of blood be placed between two pieces of 

 glass, which are afterwards pressed together with some force, 

 several of the particles, however recent the blood, will be ma- 

 terially altered. The smooth circular outline is lost, and as 

 in the former case, they appear notched. A few seem to be 

 considerably extended by die compression. When the sur- 

 face of the particles has in this way been broken into, the rup- 

 tured part exhibits an adhesive property capable of gluing it 

 to another particle or to the surface of the glass; but the par- 

 ticles in their natural state, though often drawn together or ap- 

 plied to the surface of the glass by the force of attraction, seem 

 to be nearly or quite void of adhesiveness. 



There is scarcely any fluid except serum which can be mixed 

 with the blood without more or less altering the form of its 

 particles, probably in conse(juence of some chemical change. 

 In this general result our observations accord with those of 

 Hewson and Falconar, whose experiments of this kind were 

 very numerous. We differ in some of the particulars, but I 

 reserve the detail of these for a future occasion. Tiiere is no 

 fluid which, when mixed witli the blood, produces a more rc- 



niarkablr 



