1869.] Notices of Scientific WorJis. 403 



an exhausted man, the most violent display of emotion evinced by- 

 one who is jDrostrate, or as the most brilliant efforts of the intellect 

 burst from an expiring thinker, so, too, the mind can at any time 

 assert its supremacy over the active, or even the wearied instrument 

 of its operations, and can say, " Obey me, so shall it be ! " "I 

 desire to sleep, although I have but just awoke." "I desire to 

 sleep now, and to awake at such an hour." " You need rest, but I 

 desii'e you to remain active. I will not sleep." All these things 

 we can say to our brain and it must obey ! How inconsistent are 

 these facts with the teachings of some modern physiologists, who 

 would have us believe that the brain is a self-acting thinking 

 machine, and originates the thoughts which it conveys. 



We have no space to deal with other phases of the subject, such 

 as the physical causes which exclude thought in spite of the will, 

 rendering the machine incapable of action, but trust that we have 

 said enough to show how deeply interesting and suggestive is the 

 unpretending Kttle work which has served as the basis of these 

 observations. 



On Molecular and 3Iicroscopic Science. By Mary Somerville. 

 2 vols. Murray. 



The attention which has been given of late years to the study of 

 the molecular constitution of matter, and the interesting discoveries 

 which have been made, have evidently suggested to our remarkable 

 countrywoman the work before us. Unless we are greatly mistaken, 

 Mrs. Somerville's original idea was to show, by collecting all the 

 evidence within reach, that the molecule of inert matter and the 

 organic molecule were influenced by the same set of forces or energies. 

 As we see the inorganic group of atoms com])elled to assume a 

 determinate form under the influence of forces which always mani- 

 fest, to a greater or a less extent, polarity, so we discover that the 

 organic molecule — the primary cell — is equally the result of the 

 operation of similar physical agencies. The materials which constitute 

 the amorphous mountain masses, whenever they are free to arrange 

 themselves, assume a geometric form. The microscopic examination 

 of any rock, indeed, exhibits the struggle between the desu'e — if the 

 word may be used in reference to brute matter — to crystallize, and 

 the mechanical power, pressure, w^hich prevents it. Eemove in the 

 slightest degree the pressure, and the inert molecules undulate into 

 form, and crystallizations appear — a mute prophecy, as Coleridge 

 has it, of the coming vegetation. All the elements found in the 

 organic creation, whether we take for our examples the vegetable or 

 the animal world, are discovered in the inert, inorganic consti- 

 tuents of our planet. By what processes are carbon, nitrogen, 



