OF MICROSCOPIC OBJECTS. 131 



CHAPTER VII. 



MISCELLANEOUS. 



IT must be evident to all readers that there are various objects of 

 interest to the microscopist which cannot be properly placed 

 amongst any of the forementioned classes, but must not be omitted 

 in such a guide as this professes to be. Of these may be men- 

 tioned the circulation of the blood in various animals, the' rotary 

 motion of the fluid in many plants, the best means of taking 

 minute photographs, <fec. &c. 



Perhaps the most interesting of these objects is the circulation 

 of the blood through the finer vessels of various parts of the ani- 

 mals made use of for these purposes, which parts, it is evident, 

 must be very transparent to afford a perfect view of this pheno- 

 menon. The web of the frog's foot is very frequently made use 

 of, but requires a certain arrangement, which we will now describe. 

 A piece of thin wood (Dr. Carpenter recommends cork) is taken, 

 about eight inches long and three wide ; about an inch from one 

 end is cut a hole, half or three-quarters of an inch in diameter. 

 The body of the frog is then placed in a wet bag, or wrapped in 

 wet calico, whilst the hind-foot projects ; the whole is then laid 

 upon the piece of wood so that the foot, which is left free, may 

 be extended over the hole. The web must then be spread out, 

 and secured either by threads to small pins on the wood, or the 

 pins must be driven through the web into the wood, and so kept 

 in position. A few bands of tape must be passed round the body, 

 the leg, and the wood, to prevent any disarrangement arising from 

 the animal starting, <fec. Care must be taken that the tape is not 

 too tight, else the circulation will be very slow or altogether 

 stopped. The wood must now be fixed upon the stage, with the 

 aperture under the object-glass : this is sometimes done by simply 

 binding it, or a spring is fixed so as to accomplish the same ob- 



