In whatever manner the separate parts of a constitution may be arranged, there is one general principle, etc.—Paine.
(See also Sec. 223.)
And from her fair and unpolluted flesh
May violets spring!
—Shakespeare.
249. Can is used in the indicative only. The l in could did not belong there originally, but came through analogy with should and would. Could may be subjunctive, as in Sec. 220.
250. Must is historically a past-tense form, from the obsolete verb motan, which survives in the sentence, "So mote it be." Must is present or past tense, according to the infinitive used.
All must concede to him a sublime power of action.—Channing
This, of course, must have been an ocular deception.—Hawthorne.
251. The same remarks apply to ought, which is historically the past tense of the verb owe. Like must, it is used only in the indicative mood; as,
The just imputations on our own faith ought first to be removed.... Have we valuable territories and important posts...which ought long since to have been surrendered?—A. Hamilton.
It will be noticed that all the other defective verbs take the pure infinitive without to, while ought always has to.