The existence of this reserve supply of energy is manifested in physical as well as mental effort.

Men who work with their heads and men who work with their hands, scholars and Marathon runners, must alike testify to the existence of reserve supplies of power not ordinarily drawn upon.

[Sidenote:  "Blue” Mondays]

If we do not always or habitually utilize this reserve power, it is simply because we have accustomed ourselves to yield at once to the first strong feeling of fatigue.

Evidence of this same fact appears in our feelings on different days.  How often does a man get up from his breakfast-table after a long night’s rest, when he should be feeling fresh and invigorated, and say to himself, “I don’t feel like working today.”  And it may take him until afternoon to get into his workaday stride, if, indeed, he reaches it at all.

[Sidenote:  How to Strike One’s Stride]

You cannot yourself be immune from the feeling on certain days that you are not at your best.  Somehow or other, your wits seem befogged.  You hesitate to undertake important interviews.  Your interest lags.  And though crises arise in your business, you feel weighted down and unable to meet them with that shrewd discernment and decisiveness of action of which you know yourself capable.

But you realize, in your inmost self, that if you continue to exert the will and persistently hold yourself to the business in hand, sooner or later you will warm to the work, enthusiasm will come, the clouds will be dispelled, the husks will fly.  Yet you have had no rest; on the contrary, you have, by continued conscious effort, consumed more and more of your vital energy.

[Sidenote:  The Spur of Desire]

Obviously it was not rest that you needed.

What you required was the impulse of some strong desire that should carry you over the threshold of that first inertia into the wide field of reserve energy so rarely called upon and so rich in power.

Under the lashings of necessity, or the spur of love or ambition, men accomplish feats of mental and physical endurance of which they would have supposed themselves incapable.  Here is what a certain lawyer says of his early struggles: 

[Sidenote:  How to Release Stored-Up Energies]

“When I was twenty-three years old, married, and with a family to support, I entered the law course of a great university.  Of the many students in my class, seven, including me, were making a living while studying law.

“By special arrangement, I was relieved from attendance at lectures and simply required to pass examinations on the various subjects, and was thus enabled to retain my place as principal of a large public school.  During the third and last year of my law course, I was principal of a public day school of two thousand children and an alternate night school with an enrolment of seven hundred and fifty, and I worked at the law three nights in the week and all day Sunday.