Whether it is advisable to attempt to reduce a place by blockade will depend upon the time which will probably be taken in its reduction, the force required for surrounding it, and repelling sorties from the interior or beating back a relieving army, and the expense in men and materials of taking the work by other methods. Blockades are more effective in reducing cities and towns than in taking places occupied only by a military garrison, since the presence of a large number of non-combatants in a place rapidly exhausts its store of provisions, renders epidemics more likely to break out, and by the suffering and misery resulting demoralizes the garrison, unnerves the commander, and eventually causes its fall. This justifies the apparent harshness of not allowing non-combatants to leave a beleaguered place. The steps necessary for establishing the blockade are identical with those taken for the investment in a regular siege and will be described hereafter. The capture of Paris in 1870-71 is one of the most recent and striking examples of a blockade on a large scale. SURPRISE. =2.= A sudden and unexpected attack made upon a garrison unprepared to receive it is called a =surprise=. Formerly these were of not infrequent occurrence, but with modern means of communication and methods of warfare they can hardly be looked for, except in small affairs, where, through the weakness or exhaustion of a garrison or the incapacity of its commander, the necessary and ordinary precautions for their prevention are impracticable or are neglected; or where they are brought about through treachery in the garrison, by which the gates are opened to the attack. Probably in the majority of cases attempts at surprise will be detected and defeated; but as a success is usually valuable far in excess of the losses suffered in its execution, promising opportunities for their trial should not be neglected.