(B) A and B are joint jailors, and as such, have the charge of Z, a prisoner, alternately for six hours at a time. A and B, intending to cause Z's death, knowingly co-operate in causing that effect by illegally omitting, each during the time of his attendance, to furnish Z with food supplied to them for that purpose. Z dies of hunger. Both A and B are guilty of the murder of Z. (c) A, a jailor, has the charge of Z, a prisoner. A intending to cause Z's death, illegally omits to supply Z with food; in consequence of which Z is much reduced in strength, but the starvation is not sufficient to cause his death. A is dismissed from his office, and B succeeds him. B, without collusion or co-operation with A, illegally omits to supply Z with food, knowing that he is likely thereby to cause Z's death, Z dies of hunger. B is guilty of murder, but as A did not co-operate with B, A is guilty only of an attempt to commit murder. 38. Persons concerned in criminal act may be guilty of different offences : Where several persons are engaged or concerned in the commission of a criminal act, they may be guilty of different offences by means of that act. Illustration A attacks Z under such circumstances of grave provocation that his killing of Z would be only culpable homicide not amounting to murder. B having ill-will towards Z and intending to kill him, and not having been subject to the provocation, assist A in killing Z. Here, though A and B are both engaged in causing Z's death, B is guilty of murder, and A is guilty only of culpable homicide. 39. "Voluntarily": A person is said to cause an effect "voluntarily" when he causes it by means whereby he intended to cause it, or by means which, at the time of employing those means, he knew or had reason to believe to be likely to cause it. Illustrations A sets fire, by night, to an inhabited house in a large town, for the purpose of facilitating robbery and thus causes the death of a person. Here, A may not have intended to cause death, and may even be sorry that death has been caused by his act; yet, if he knew that he .was likely to cause death; he has caused death voluntarily. 40. "Offence": Except in the chapters and sections mentioned in clauses 2 and 3 of this section, the word "offence" denotes a thing made punishable by this Code. In Chapter IV, Chapter V-A and in the following sections, namely, Sections 64, 65, 66, 67, 71, 109, 110, 112. 114, 115, 116, 117, 187, 194, 195, 203, 211, 213, 214. 221, 222, 223. 224, 225, 327, 328.329,330.331,347,348, 388, 389 and 445, the word "offence" denotes a thing punishable under this Code, or under, any/special or local law as hereinafter defined. And in Sections 141, 176, 177, 201, 202, 212, 216 and 441 the word "offence" has the same meaning when the thing punishable under the special or local law is punishable under such law with imprisonment for a term of six months or upwards, whether with or without fine.