

EXPLANATION OF THE PLATES. 



PLATE XLIII. 



Fig. 1. A portion of a voluntary muscle of a foetus about 

 three months old, magnified 670 diameters, present- 

 ing numerous nuclei, some of which are embedded 

 in the fibres, and others lie between them. At this 

 early period the fibres are formed of but few 

 fibrillae. The small size of these fibres in comparison 

 with those of the adult, and which are represented 

 in fig. 6., is worthy of note. 670 diameters. 



2. Illustrates the development of the inelastic form of 



fibrous tissue from nucleated and granular cells. 

 This figure was also taken from a foetus at about 

 the third month. 



3. A portion of dartos magnified 350 diameters, show- 



ing the different structures which enter into its 

 composition, viz., the blood vessels, the bands of 

 elastic fibrous tissue, and lastly, the bundles of 

 inelastic fibrous tissue. 



4. A transverse section of a portion of one of the cor- 



pora cavernosa penis, showing the apertures of the 

 vessels or cells of which they are principally com- 

 posed, as well as the walls of those cells which are 

 formed, not of nucleated elastic tissue, but of 

 branched and reticular elastic filaments. This 

 figure is magnified only a few diameters. 



5. Muscular fibres of voluntary muscle, disposed in a 



zigzag manner ; this disposition was formerly con- 

 sidered to be normal, and to be that assumed by 

 the fibres of every muscle in a state of contraction, 

 a view which is certainly erroneous ; it is encoun- 

 tered in a greater or less degree in all fried and 

 roasted meats. 



6. Striped muscular fibres, magnified 670 diameters. It 



will be seen from the figure, that the surface of 

 each fibre is raised into ridges with a narrow space 

 intervening between each ridge, and further, that 



