178 Sir Everard Home on the changes the blood 
same size ; but varied a little in dimension, even in the same 
part of the brain. In general, however, he found them, both 
in the brain proper and in the cerebellum, to be more than 
eight times smaller than a globule of the blood. The most 
powerful microscopes did not enable him to discover any thing 
satisfactory respecting their structure.” 
“ These observations have, within these few years, been 
prosecuted on a much more extensive scale, by Joseph and 
Charles Wenzel.* They have uniformly found, that the 
white nervous matter seemed as if entirely composed of ex- 
tremely small globules or corpuscules of a roundish form, 
putting on the appearance of little cells, filled with a proper 
medullary substance. No estimate is given of the dimensions 
of the globules, but they describe them as being exceedingly 
minute, and as being all pretty nearly of the same size. 
They seemed to adhere very closely to each other, without 
any apparent connecting medium. The globular appearance 
continued distinctly perceptible in portions of the substance, 
which had been long exposed to the action of rectified spirit 
of wine and muriatic acid ; nor was it even destroyed by 
steeping the matter in alcohol, and then drying it.” 
The statements contained in both of these extracts confirm, 
in the most satisfactory manner, Mr. Bauer's observations, 
although in many respects, they are deficient in point of ac- 
curacy. - 
Having laid before the Society all I have to offer, respecting 
the appearances of the globules of the blood from which the 
colouring matter had been discharged, I shall endeavour to 
explain in what manner blood, in the act of coagulation, 
* De Penitior. Struct. Cereb. p. 24. 
