Microscopical Essays. 147 



other fmall fifh may be applied in the fame manner, or tied on a 

 flip of flat glafs, and be thus laid before the micro fcope. 

 Flounders, eels, and gudgeons, are to be had almoft at any time 

 in London.— N. B. By filling the tube with water, when an eel is 

 ufe.d, it will in a great meafure prevent the fliminefs of the eel 

 from foiling the glafs. 



To view the particles of the blood, take a fmall drop of it 

 when warm, and fpread it as thin as poflible upon a flat piece of 

 glafs. By diluting it a little with warm water, fome of the larger 

 globules will divide from the fmaller, and many of them will be 

 fubdivided into fmaller ones : or a little drop of blood may be 

 put into a capillary tube of glafs, and be then prefented before 

 the micro fcope. Mr. Baker advifes the mixing the blood with 

 a little warm milk, which, he fays, will caufe the unbroken par- 

 ticles to be very diftinaiy feen ; but the mod accurate obferver of 

 thefe particles was Mr. Hewfon, and he fays, they have been 

 termed globules with great impropriety, being in reality flat 

 bodies. When we confider how many ingenious perfons have 

 been employed in examining the blood with the beft microfcopes, 

 it appears furprizing that the figure of the. particles fhould be 

 miftaken • but the wonder is lefiencd when we reflect how many 

 obvious things are overlooked, till our attention is particularly 

 direcled towards them ; and befides, the blood in the human fub- 

 je&, and in quadrupeds, is fo full of thefe particles, that it is 

 with great difficulty they can be feen feparate until the blood is 

 diluted. It was by difcovering a proper method to effed this that 

 Mr. Hewfon was indebted for his fuccefs. He diluted the particles 

 with ferum, in which they would remain undrffolved, and as he 

 could dilute them to any degree w ith the ferum, he could eafily 



