230 MENTAL AND PHYSICAL EXERCISE. 



downwards, or alternately in all these directions, the 

 straight muscles, (Fig. 104,) are thrown into alternate 

 contraction, and relaxation, at the mandate of the brain. 

 Meantime the visual portion of the eye furnishes us with 

 a picture of the landscape, the different parts of which 

 we thus examine by means of the mechanical portion. 

 Is it not plain, that infinite wisdom and Almighty power 

 only, could have devised and constructed such machin- 

 ery as this ? 



Personal temperament, and disposition, accounted for. 

 It is on the same principles, that we can account for 

 the difference which we observe in persons, with respect 

 to their temperaments, or dispositions, as already stated. 

 When we see a person of feeble muscular powers, easi- 

 ly thrown into agitation, turning pale, or fainting by 

 slight causes, and morbidly sensitive to every nervous 

 impression, we may conclude that in such persons the 

 sentinet nervous system predominates ; or, in other 

 terms, that the nerves w r hich carry impressions to the 

 brain, are either more highly developed, or are in a more 

 sensitive state, than those concerned in muscular con- 

 traction. In such persons the flesh is commonly soft to 

 the touch, and has a pallid hue. On the contrary, 

 in persons where there is great muscular power, as indi- 

 cated, not only by the strong outlines of the muscles 

 themselves, but also by the capability of enduring great, 

 and continued bodily exertions, and by a temperament 

 void of excessive sensibility, being able to bear strong 

 nervous impressions with little indication of nervous 

 feeling ; w^e may conclude that in such persons the mo- 

 tor nerves, or those concerned in muscular contraction, 

 predominate over those subservient to sensation. In 

 such persons the muscles are commonly rigid to the 

 touch, even when relaxed, presenting a striking contrast 

 with the morbid softness of these parts, in persons of 

 excessive nervous mobility. 



Natural Disposition may be modified. Although, as 

 we have supposed, and the fact cannot be doubted, that 

 there is a natural difference in different persons, with 

 respect to the distribution of the sentient and muscular 



