As a supplement to this rule, the usages of war recognize the desirability of not employing severer forms of violence if and when the object of the war may be attained by milder means, and furthermore that certain means of war which lead to unnecessary suffering are to be excluded. To such belong:
The use of poison both individually and collectively (such as poisoning of streams and food supplies[47]) the propagation of infectious diseases.
Assassination, proscription, and outlawry of an opponent.[48]
The use of arms which cause useless suffering, such as soft-nosed bullets, glass, etc.
The killing of wounded or prisoners who are no longer capable of offering resistance.[49]
The refusal of quarter to soldiers who have laid down their arms and allowed themselves to be captured.
The progress of modern invention has made superfluous the express prohibition of certain old-fashioned but formerly legitimate instruments of war (chain shot, red-hot shot, pitch balls, etc.), since others, more effective, have been substituted for these; on the other hand the use of projectiles of less than 400 grammes in weight is prohibited by the St. Petersburg Convention of December 11th, 1868. (This only in the case of musketry.[50])
He who offends against any of these prohibitions is to be held responsible therefore by the State. If he is captured he is subject to the penalties of military law.
Colored Troops are “Blacklegs.”
Closely connected with the unlawful instruments of war is the employment of uncivilized and barbarous peoples in European wars. Looked at from the point of view of law it can, of course, not be forbidden to any State to call up armed forces from its extra-European colonies, but the practise stands in express contradiction to the modern movement for humanizing the conduct of war and for alleviating its attendant sufferings, if men and troops are employed in war, who are without the knowledge of civilized warfare and by whom, therefore, the very cruelties and inhumanities forbidden by the usages of war are committed. The employment of these kinds of troops is therefore to be compared with the use of the instruments of war already described as forbidden. The transplantation of African and Mohammedan Turcos to a European seat of war in the year 1870 was, therefore, undoubtedly to be regarded as a retrogression from civilized to barbarous warfare, since these troops had and could have no conception of European-Christian culture, or respect for property and for the honor of women, etc.[51]
2. Capture of Enemy Combatants
Prisoners of War.
If individual members or parties of the army fall into the power of the enemy’s forces, either through their being disarmed and defenseless, or through their being obliged to cease from hostilities in consequence of a formal capitulation, they are then in the position of “prisoners of war,” and thereby in some measure exchange an active for a passive position.