WITH THE MICROSCOPF. 1 23 



muscles is well shown in a transverse section of the pectoral muscle 

 of a teal (Querquedula crecca), which has been put upon the stretch, 

 and allowed to become perfectly dry. A section cut as thin as pos- 

 sible, may be re-moistened with water, and examined in the usual 

 manner. The position of the vessels, their relation to the fibres, and 

 the character of capillary network are easily demonstrated in speci- 

 mens which have been injected with transparent Prussian blue or 

 carmine injection. 



220. Sarcoicmiiia. The fibre of the skate, as Mr. Bowman has 

 shown, is remarkably well adapted for showing the sarcolemma, as 

 the sarcous matter may be ruptured while the investing membrane 

 remains entire, and may be thus easily demonstrated. A few of the 

 long fibres from the fin may be spread out upon a piece of glass with 

 the aid of needles, and in this operation it will be found that the 

 rupture of the sarcous matter in the interior has taken place. Sar- 

 colemma is well seen in pi. XXVIII, fig. 184. This membranous tube 

 may be also beautifully shown in the muscular fibres of a water- 

 beetle, particularly in those of the large dytiscus. 



221. Branched Muscular Fibres. Several modifications of striped 

 muscle have been described of late years, and it is desirable to con- 

 sider the best methods of demonstrating a few of the most impor- 

 tant of these. Branched muscular fibres have been found in the 

 heart, but the finest are not very easily demonstrated. Fibres of this 

 nature may, however, be shown to exist in great abundance in the 

 tongue of the frog (as was pointed out by Kolliker), from which 

 organ they may generally be obtained as follows : the tongue is to 

 be separated from the animal, and boiled for a few moments in water ; 

 the mucous membrane is cautiously dissected off from a small por- 

 tion, and a few minute pieces are to be carefully snipped off with 

 scissars, from the edge of the tongue, just beneath the mucous mem- 

 brane. These are to be torn with very delicate needles, and then 

 examined with a quarter of an inch object-glass. In this manner 

 very perfect fibres may generally be found ; but care must be taken 

 not to boil the tongue for too long a time, in which case the fibres 

 become too brittle to admit of separation. These branched fibres 

 are very beautiful objects. In good specimens they are seen to 

 ramify after the manner of the branches of a tree, gradually becom- 

 ing thinner, until each terminates in a delicate extremity, which is of 

 a tendinous nature, and is incorporated with the sub-mucous areolar 

 tissue or corium. The transverse striae may be observed in the 

 thinnest branches, but cease some distance from the terminal 

 extremity of the fibre. Branched fibres also exist in the upper lip of 

 the rat, and in other situations. Beautifully delicate branched 



