He recognises three degrees of muscular irritability, to which he has given the names of active efficient, passive efficient, and negative,--though doubtless he would recognize the probability that the line separating the first from the second may not always be easily traced, and that, though there is a most definite distinction between the second and the third, the actual position of the boundary line has not as yet been determined. In other words, so far as the first and second states are concerned, there are not two degrees only, but many. As regards the third or negative state, which is only another way of describing death, there is, of course, only one degree, though the evidence as to the existence of this state may be more or less complete and obvious. Dr. Richardson defines the active efficient state of muscular irritability as that "represented in the ordinary living muscle in which the heart is working at full tension, and all parts of the body are thoroughly supplied with blood, with perfection of consciousness in waking hours, and, in a word, full life." The second, or passive efficient state, "is represented in suspended animation, in which the heart is working regularly but at low tension, supplying the muscles and other parts with sufficient blood to maintain the molecular life, but no more." The third of these states--the negative--"is represented when there is no motion whatever of blood through the body, as in an animal entirely frozen." With the first and third of these states I have in reality nothing to do, unless indeed it could be shown that the third or negative state can be produced without causing death. Perhaps in assuming, as I did above, that this state is identical with the state of the dead, I was, in fact, assuming what science has yet to demonstrate. I may at any rate, however, say without fear of valid contradiction, that science has as yet never succeeded in showing that this negative state may be attained even for a moment without death ensuing; and the probability (almost amounting to certainty) is that death and this change of state have in every instance been simultaneous. Dr. Richardson speaks of the second stage as that in which animation is _usually_ suspended; but he does not show that the third stage can even possibly be attained without death.