To prevent this, the teacher should exercise double vigilance at such a time.

He should often address questions to individuals alone, especially to those most likely to be inattentive and careless, and guard against the ingress of every abuse which might, without close vigilance, appear.
With these cautions, the method here alluded to will be found to be of very great advantage in many studies; for example, all the arithmetical tables may be recited in this way; words may be spelled, answers to sums given, columns of figures added, or numbers multiplied, and many questions in history, geography, and other miscellaneous studies answered, especially the general questions asked for the purpose of a review.
But, besides being useful as a mode of examination, this plan of answering questions simultaneously is a very important means of fixing in the mind any facts which the teacher may communicate to his pupils.
If, for instance, he says some day to a class that Vasco de Gama was the discoverer of the passage round the Cape of Good Hope, and leaves it here, in a few days not one in twenty will recollect the name.

But let him call upon them all to spell it simultaneously, and then to pronounce it distinctly three or four times in concert, and the word will be very strongly impressed upon their minds.

The reflecting teacher will find a thousand cases in the instruction of his classes, and in his general exercises in the school, in which this principle will be of great utility.

It is universal in its application.