An excerpt from
http://caselaw.findlaw.com/mi-suprem.../1106701.html#, last paragraph is interesting.
The statement of the governing principles of self-defense as set forth in People v. Doe, 1 Mich. 451, 456-457 (1850), is indicative of the common-law rules that were in place when the Legislature enacted Michigan's murder statutes just four years earlier. These principles remain apropos today and have not been modified since their implicit codification more than 150 years ago:
First. That a man who, in the lawful pursuit of his business, is attacked by another under circumstances which denote an intention to take away his life, or do him some enormous bodily harm, may lawfully kill the assailant, provided he use all the means in his power, otherwise, to save his own life or prevent the intended harm; such as retreating as far as he can, or disabling his adversary without killing him, if it be in his power.[21]
Secondly. When the attack upon him is so sudden, fierce and violent, that a retreat would not diminish, but increase his danger, he may instantly kill his adversary without retreating at all.
Thirdly. When from the nature of the attack, there is reasonable ground to believe that there is a design to destroy his life, or commit any felony upon his person, the killing of the assailant will be excusable homicide, although it should afterwards appear that no felony was intended. [Emphasis supplied.]