WITH THE MICROSCOPE. I I/ 



the tissues, coagulated and opaque after the addition of different 



reagents. 



It is, however, a fact that in many textures nothing is to be 

 seen if the ordinary methods of examination are pursued, while 

 by special processes wonderful nerve plexuses and other things 

 most definite may be demonstrated. Some objectors will perhaps 

 assert that the processes have formed these things ! 



From what has been just observed it must be evident, that the 

 clear demonstration of the structure of any individual organ of the 

 body is a somewhat difficult matter, and requires a considerable 

 amount of knowledge of the chemical and physical characters of 

 the tissues, as well as patient investigation and earnest study. 



212. General Directions for the Examination and Preservation of 

 a Soft Tissue. Suppose a portion of muscular fibre is to be examined 

 under the microscope. A small piece may be removed with a pair 

 of very fine scissars, and placed carefully upon the glass slide. With 

 the aid of two needles it may be torn into very small shreds, and it 

 is then moistened with a little water dropped upon it from the finger, 

 or from a pipette, or from the wash-bottle ; or instead of water, a 

 drop of serum, of syrup, or of glycerine may be added to it, but in 

 this case it should be allowed to remain in the syrup or glycerine for 

 some time, so that it may be thoroughly permeated by the more 

 dense solution. Next a square or circular piece of thin glass held 

 in a pair of fine forceps is gently breathed upon and applied to the 

 surface of the liquid, being brought into contact with it, first on one 

 side, and then allowed to fall down very gradually with the aid of a 

 needle or piece of fine wire placed underneath one edge, until it is 

 completely wetted, pi. XXII, fig. 142. Lastly, any superfluous fluid 

 is to be absorbed by a cloth, or a small piece of fine sponge or 

 blotting paper, and the slide placed in the field of the microscope 

 for examination. 



It is important to prevent the entrance of air bubbles, pi. XIX, 

 fig. 122, during the application of the thin glass cover, and if any are 

 visible in the tissue or surrounding fluid before it is applied, it will be 

 better to wait a few minutes until they rise to the surface of the liquid 

 and burst, before allowing the thin glass cover to fall in its place. 

 While time is allowed for this to take place, the specimen should be 

 covered with a small glass shade to prevent dust falling upon it, 

 pi. XVI, fig. 87, p. 47. 



It is advisable not to remove too much of the fluid, for fear the 

 thin glass should press so heavily upon the preparation, as to cause 

 the several structures of which it is composed to be squeezed to- 

 gether and the specimen rendered confused. The observer will find 



