194 Mr F. Cohn on the Contractile Filaments in Thistles. 
death. Further,in Ameba, Actinophrys, Diflugia, Arcella, 
and the Rhizopoda generally, the processes are manifestly 
actively elongated, while these organisms, by stimulus as by 
death, are contracted into globules. Similar phenomena are 
exhibited by Hydra viridis, &. In all these organisms 
there is a permanent contraction in death, which yields 
only to diffluence of the body by decomposition. There is 
no final relaxation, as in true muscular tissue. 
The author gives some figures representing the micro- 
scopic appearances of the cells of the filament in the 
expanded and contracted conditions, but which it is unne- 
cessary to reproduce here.* 
On Muscular Power. By H. F. Baxter, Esq. 
§ 1. On the Mechanical Power of Muscles exerted during Muscular 
Contraction. § 2. On the Application of the Principle of Con- 
servation of Force or Conservation of Energy to the explanation 
of Physvological Phenomena. 
That muscular contraction is accompanied with the de- 
velopment of electrical action, I have already shown on a 
former occasion,t thus confirming the results previously 
obtained by Matteucci and Du Bois Reymond. That heat 
is evolved during muscular contraction, has been shown by 
Breschet and Becquerel,{ and by Matteucci. That changes 
of a chemical nature take place in muscles, in consequence 
of muscular action, has been established by the experi- 
ments of Liebig, Helmholtz, and others; and Matteucci] 
has ascertained that, during muscular contraction, carbonic 
* There appears to be some mistake in the representation of the section in 
fig. d (l. c. p. 869): it purports to be a transverse section of the filament, and 
the more or less hexagonal outline of the cells would bear out the assertion ; 
yet I do not understand how ¢ransverse corrugation could appear in a trans- 
verse section at all in the way represented in the figure, almost like the edge 
of a close frill.—A. D. 
t Philosophical Magazine, 1855. Essay on Organic Polarity, 1860. 
+ Traité de l’Electricité, tom. iv. p. 9. 
?# Annales de Chimie et de Physique. Juin, 1856. 
| Ibid. 
