Experiments on the Oxides and Salts of Uranium. 91 
and 1 of acid, we obtain the number 80 as the equivalent of 
oxide of uranium, and 72 as that of the metal. Neither iodine 
nor the hydriodates occasion any precipitation in solutions of 
uranium, but ferrocyanate of potassa occasions a fine reddish- 
brown precipitate in them all, and this although they are con- 
siderably acid. 
The above experiments were undertaken with a view of de- 
termining the equivalent number of uranium; but, of the various 
compounds that have been examined, the sulphates only appear 
to afford results that can be deemed at all satisfactory; and 
even these are too much at variance to enable us to assume their 
analyses as the foundation of a prime equivalent number. 
Art. VIII. A Review of some of the General Principles of 
Physiology, with the Practical Results to which they have 
led. By A. P.W. Puiuir, M. D.,F.R.S. Edinb. 
[Concluded from page 276, Vol. XIII.] 
We have now taken a rapid survey of the general laws of the 
muscular and nervous systems, and the means by which these 
laws have been ascertained. The power of the muscles we 
found independent of the influence of the nervous system, which 
stands in no other relation to them, but that of a stimulus. 
This power appears, from what has been said, to be of the same 
nature in all muscles; the means of exciting it alone varying 
in those of voluntary and involuntary motion. The nervous 
system, we have seen, besides affording the sole stimulus of the 
former and an occasional stimulus of the latter set of muscles, 
maintains, by its action on the blood, the secreting and other 
assimilating processes, and the due temperature of the animal, 
and is the means of conveying impressions to and from its more 
central parts, the brain and spinal marrow; there being no evi- 
dence that impressions are ever communicated from one nerve 
to another, independently of the intervention of one of these 
organs: a position farther illustrated by the able investigations 
