as observed in the Tongue of the living Frog, Toad, $c. 285 



jected some time to the experiment, the striae become indistinct 

 and finally disappear. In some instances the muscular fibre 

 appeared to have its contents broken up in separate fragments, 

 each of which included several of the muscular striae. Similar 

 results were obtained from the examination of the tongue of 

 the frog, except that frequently none of the striae were to be 

 seen in any portion of it. Their non-appearance I at first 

 attributed to their more rapid disappearance ; but notwith- 

 standing every care I took to perform the experiment expedi- 

 tiously, I found that in many instances they were entirely 

 wanting : when examined after death (if the tongue has not 

 been previously experimented upon) I have always succeeded 

 in detecting them. Dilute nitric acid in these cases was found 

 to render the striae more distinct. The striae, as they appear 

 in these animals, are sometimes perpendicular to the axis of 

 the fibre, at other times inclining slightly to it; and even in 

 some instances the lines are bent in the middle. Their di- 

 stance from each other, though generally equal, was sometimes 

 irregular. 



In all my observations I have never detected any angular 

 deviation when the muscular fibres contracted, as asserted by 

 Prevost and Dumas. During the contraction the sides of the 

 fibres are merely seen to become more dark and distinct, and 

 perhaps more thick; but in general, with high magnifying 

 powers, the movement is too quick to be followed, and the 

 fibre loses the exact focus of the instrument: neither have I 

 detected any displacement or alteration of the striae, such as 

 many anatomists have imagined to take place. 



In the preceding observations I have endeavoured to show 

 some of the results to be obtained by a careful microscopic 

 observation of this organ, so important in its functions, and 

 containing within it all the principal tissues of the animal 

 frame. I have yet to treat of the nerves and lymphatics, 

 whose ultimate distribution is beautifully displayed. It is 

 unnecessary to point out all the facts which I consider novel 

 in this communication ; but as some of the most interesting, I 

 may refer to the alterations in muscular fibre during life, the 

 circulation in the glands, and the entire separation, in certain 

 cases, of the spherical from the other particles of the blood. 

 Kensington, August 15, 1846. 



Additional Observations. 



Recent observations have enabled me to decide the much- 

 agitated question as to the formation of pus, and its origin 

 from the extravasation of the colourless or spherical corpus- 



