396 THE POPULAR SCIENCE MONTHLY. 



blood has unduly flowed to the brain ; muscular exei'cise draws it oiF. 

 The oxidation of the tissues has been retarded ; muscular exercise is 

 the most direct mode of increasing it. But definite observations teach 

 us that these two beneficial effects are arrested at the fatigue-point ; 

 so that the exercise at last contributes not to the refreshment, but to 

 the further exhaustion of the system. 



2. The real point before us is, What do we gain by dropping one 

 form of activity and taking up another? This involves a variety 

 of considerations. 



It is clear that the first exercise must not have been pushed so far 

 as to induce general exhaustion. The raw recruit, at the end of his 

 morning drill, is not in a good state to improve his arithmetic in the 

 military schoolroom. The musical training for the stage is at times 

 so severe as to preclude every other study. The importance of a par- 

 ticular training may be such that we desire for it the whole available 

 plasticity of the system. 



It is only another form of exhaustion when the currents of the 

 brain continue in their set channels and refuse any proposed diversion. 



There are certain stages in every new and difficult study, wherein 

 it might be well to concentrate for a time the highest energy of the 

 day. Generally, it is at the commencement ; but whatever be the 

 point of special difficulty, there might be a remission of all other 

 serious or arduous studies, till this is got over. Not that we need 

 actually to hny aside everything else ; but there are, in most studies, 

 many long tracts where we seem in point of form to be moving on, 

 but arc really repeating substantially the same familiar efforts. It 

 would be a felicitous ideal adjustment, if the moments of strain in one 

 of the parallel courses were to coincide with the moments of ease in 

 the rest. 



Hardly any hind of study or exercise is so complicated and many- 

 sided as to press alike upon all the energies of the system ; hence 

 there is an obvious propriety in making such Aariations as would 

 leave unused as few of our faculties as possible. This principle neces- 

 sarily applies to every mental process acquirement, ])roduction, and 

 enjoyment. The working out of the principle supposes that we are 

 not led away by the mere semblance of variety. 



Let us endeavor to assign the difi"erences of subject that afford 

 relief by transition. 



There are many kinds of change that are merely another name for 

 simple remission of the intellectual sti-ain. When a severe and diffi- 

 cult exercise is exchanged for an easy one, the agreeable effect is due 

 not to what we engage in, but to what mo are relieved from. For 

 letting down the strain of the faculties, it is sometimes better to take 

 up a light occupation for a time than to be totally idle. 



The exchange of study for sport has the twofold adA-antage of 

 muscular exercise and agreeable play. To pass from anything that 



