THE USE OF THE MICROSCOPE. 351 



TABLE V. 



KIDNEY. MUSCULAR FIBRE. PIG'S-SKIN. PITH. WOOD. SPIRAL 



VESSELS. -VALLISNERIA. 



31. Make thin sections of the sheep's kidney upon the table, and 

 after washing them, subject them to examination with the 

 inch, and afterwards with the quarter. Some may be examined 

 in water and others in glycerine, one section should be mounted 

 in the mixture of gelatine and glycerine, 106. Observe 

 the different characters of the tubes in the central and in the 

 cortical portions of the organ, and endeavour to make out the 

 following structures : Epithelium, basement membrane of the 

 tubes, Malpigldan bodies and capillary vessels lying between the tubes, 

 p. 142. The arrangement of the vessels may be satisfactorily 

 demonstrated in an injected specimen. Table VII. 



32. Take a very small fragment of the muscular fibre of the skate or 



eel, and after tearing it up with needles, moisten it with water, 

 and cover it with thin glass. Endeavour to find elementary 

 fibres in which the tube of sarcolemma remains entire while the 

 sarcotis tissue within is ruptured. 212, 220, pi. XXVIII, 

 fig. 184. 



33. The portion of pig's-skin on the table has been allowed to dry by 



exposure to the air. Thin transverse sections are to be removed 

 with a sharp knife, and subsequently moistened with water. In 

 this manner a very thin section may be obtained, which soon 

 regains its normal appearance. It may be mounted in any of 

 the preservative fluids before alluded to. 150. 



34. Cut thin sections of the cornea and sclerotic of the eye which have 

 been allowed to dry after having been pinned out on a board ; 

 soak them in a drop of water for twenty minutes or more, and 

 examine them first with an inch object-glass and afterwards with 

 a quarter. 150. 



35. Cut a thin section of the pith of the rush and examine it as a dry 

 object ; afterwards place it in fluid. Observe the air within 

 many of the cells. 



36. Demonstrate the circulation in the cells of vallisneria spiralis. 

 259, pi. XXXVIII, figs. 243, 244- 



37. Wash some pieces of the sea-weed in plain water, and preserve 



some of them in glycerine, and others in solution of chloride of 

 calcium. 260. 



