92 Dr. Barry's renewed Inquiries concerninff the 



muscle from the Flea, in which, from its enormous leaps, some- 

 thing similar would he thought be found. The author accord- 

 ingly examined some of these, and had the satisfaction to find in 

 them a degree of muscular relaxation even higher than that he 

 had observed in the grasshopper. In the two figures, fig. 16 and 

 fig. 5, the parts in fig. 16 marked b, b, correspond to b', b' in 

 fig. 5. From a comparison of these two figures, it will be at 

 once seen how the extended b, b in fig. 16, pass in contraction 

 into the narrower b', b', fig. 5. Similar conditions no doubt 

 exist in other animals, but perhaps nowhere are they more re- 

 markable and constant than in those just mentioned. The 

 observation may possibly induce some to bestow their attention 

 upon this subject when examining leaping insects as well as 

 other animals. 



The author repeats a drawing he gave in the Phil. Trans, for 

 1843, of an arteiy from the pia mater of the Rabbit, fig. 17, of 

 which the following is an explanation : — a, longitudinal muscular 

 fibrils, repi-esented merely by rows of dots, except a single one 

 on the left side in which is shown the double spiral ; b, outline 

 of a fibril surrounding the longitudinal ones ; c, double spiral 

 structure oib ; d, blood-corpuscles, for the most part young and 

 very small ; e, a line denoting the inner membrane of the artery. 

 He then gives a figure, fig. 18, representing more distinctly the 

 double spiral structure of such a fibril as b in fig. 17. 



His observations on the history of development of muscle are 

 given in detail, with many illustrative di'awings ; but as only a 

 part of the latter can be given in this abstract, it is not intended 

 to offer here more than the substance of the principal facts he 

 obseiTed, which were as follows : — 



Cells having arranged themselves as at a, fig. 19, and their 

 membranes having passed through the states b and c in the same 

 figure, and a tube having been thus formed (stages known to 

 other observers), columns of compound cytoblasts are seen within 

 the tube, fig. 20 b,c; which cytoblasts have descended by divi- 

 sion from the nuclei of the primitive cells, fig. 19 «. (The com- 

 pound cytoblasts in these columns are arranged with such regu- 

 larity as to produce, and explain the nature of, the striaj seen by 

 Schwann, fig. 20 a.) The membrane of the tube disappears, not 

 forming, as Schwann thought, a permanent sarcolemma; and 

 the columns of compound cytoblasts having passed into coils of 

 cells, fig. 13 fl, a spiral is formed of them, as shown by the dia- 

 gram b in the latter figure. A central row of cell-germs is left 

 for the formation of future spirals ; and the spiral fii'st formed 

 divides, and, as above shown, passes into membrane — the fii'st 



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