May 29, 1879] 



NATURE 



107 



the claw is stronger and stronger. This, too, accords 

 ■with the habits of the crayfish, which will almost sooner 

 die than let go its prey when seized. Thus between the 

 two chief muscles of the crayfish there is a difference at 

 least as considerable as between the striated and non- 

 striated muscles of vertebrates. 



SUSPENDED ANIMATION 



THE statements in the Times of Monday, which, under 

 the head of "A Wonderful Discovery," are copied 

 from the Brisbane Courier, seem greatly to have astonished 

 the reading public. To what extent the statements are 

 true or untrue it is impossible to say. The whole may be 

 a cleverly-written fiction, and certain of the words and 

 names used seem, according to some readers, to suggest 

 that view ; but be this so or not, I wish to indicate that 

 some part, at all events, of what is stated might be true, 

 and is certainly within the range of possibility. 



At once let me state that the discovery, so called, which 

 is described in the communication under notice, is not in 

 principle new. On the subject of suspension of anima- 

 tion I have myself been making experimental inquiries 

 for twenty-five years at least, and have communicated to 

 the scientific world many essays, lectures, and demon- 

 strations relating to it. I have twice read papers bearing 

 on this inquiry to the Royal Society, once to the British 

 Association for the Advancement of Science, two or three 

 times in my lectures on Experimental and Practical 

 Medicine, and published one in Nature. In respect to 

 the particular point of the preservation of animal bodies 

 for food, I dwelt on this topic in the lectures delivered 

 before the Society of Arts in April and May of last year, 

 1878, explaining very definitely that the course of re- 

 search in the direction of preservation must ultimately lead 

 to a process by which we should keep the structures of 

 animals in a form of suspended molecular life. 



Let me next point out what, by experiment, is known 

 as to the possibility of suspending animal life. 



If an animal perfectly free from disease be subjected 

 to the action of some chemical agents or physical agencies 

 which have the property of reducing to the extremest 

 limit the motor forces of the body, the muscular irrita- 

 bility, and the nervous stimulus to muscular action, and 

 if the suspension of the muscular irritability and of the 

 nervous excitation be made at once and equally, the body 

 even of a warm-blooded animal may be brought down to 

 a condition so closely resembling death, that the most 

 careful examination may fail to detect any signs of life. 

 I have shown in a Croonian lecture that there are three 

 degrees of muscular irritability to which I have given 

 the names of active efficient, passive efficient, and 

 negative. The first of these states is 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 of 

 these states 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 sustain the molecular life, but no more. The 

 third of these states is represented when there is no 

 motion whatever of blood through the body, as in an 

 animal entirely frozen. 



The second stage, the stage of passive efficiency, is 

 that in which animation is usually suspended. The con- 

 dition is a close semblance to the third stage, but differs 

 from it in that under favouring circumstances the whole 

 of the phenomena of the active efficient stage may be 

 perfectly resumed, the heart suddenly enlarging in volume, 

 from its filling with blood, and reanimating' the whole 

 organism by the force of its renewed stroke, in full tension. 



So far as we have yet proceeded, the whole phenomena 

 of restoration from death are accomplished during this 



stage. To those who are not accustomed to see them, 

 they are no doubt very wonderful, looking like veritable 

 restorations from death. They surprise even medical men 

 the first time they are witnessed by them. 



At the meeting of the British Medical Association at 

 Leeds, a member of the Association was showing to a 

 large audience the action of nitrous oxide gas, using a 

 rabbit as the subject of his demonstration. The animal 

 was removed from the narcotising chamber a little too 

 late, for it had ceased to breathe, and it was placed on the 

 table, to all appearances dead. At this stage I went to 

 the table, and by use of a small pair of double-acting 

 bellows restored respiration. In about four minutes 

 there was revival of active irritability in the abdominal 

 muscles, and two minutes later the animal leaped again 

 into life, as if it had merely been asleep. There was 

 nothing remarkable in the fact, but it excited, even in so 

 cultivated an audience as was then present, the liveliest 

 surprise. 



The time during which an animal body may be capable 

 of re-animation from the state of passive efficiency 

 depends altogether on one circumstance, viz., whether the 

 blood, the muscular fluid, and the nervous fluid remain, 

 in a condition which I have defined in another essay as 

 the aqueous condition, or whether these fluids have 

 become pectous. If the fluids remain in the aqueous 

 state, the period during which life may be restored is left 

 undefined. It may be a very long period, including weeks, 

 and possibly months, granting that decomposition of the 

 tissues is not established, and even after a limited process 

 of decomposition, there may be renewal of life in cold- 

 blooded animals. But if pectous change begins in any 

 one of the structures I have named, it extends Uke a 

 crystallisation quickly through all the structures, and 

 thereupon recovery is impossible, for the change in one 

 of the parts is sufficient to prevent the restoration of all. 

 Thus the heart may be beating, but the blood being 

 pectous it beats in vain ; or the heart may beat and the 

 blood may flow, but the voluntary muscles being pectous, 

 the beating is in vain ; or the heart may beat, the blood 

 may flow, and the muscles may remain in the aqueous 

 condition, but the nerves being pectous the circulating 

 action is in vain ; or sometimes the heart may come to 

 rest and the other parts may remain susceptible, but the 

 motion of the heart and blood not being present to 

 quicken them into activity, their life is in vain. 



The problem physiologically before us is as follows : — 

 Can the second or passive efficient stage of fife be by any 

 artificial methods secured, so that all the vital parts may 

 be held in suspended animation, working at the lowest 

 possible expenditure of vital power t 



Experimental research and experience alike show the 

 certain possibility of temporarily producing this state. 

 Both show that there are agents and agencies by which 

 life may be reduced to the low ebb necessary for suspen- 

 sion of active life, and at the same time the aqueous 

 conditions of the colloidal fluids may be maintained. 

 Cold is the first and most efficient of these agencies. 

 The blood and the colloidal animal fluids derived from 

 it are all held in the aqueous condition of colloidal matter 

 by exposure to cold at freezing-point. At this same point 

 all vital acts, e.xcepting, perhaps, the motion of the heart, 

 may be temporarily arrested in an animal, and then some 

 animals may continue apparently dead for long intervals 

 of time, and may yet return to life under conditions 

 favourable to recovery. 



In one of my lectures on death from cold, which I 

 dehvered in the winter session of 1867, some fish, which, 

 during a hard frost, had been frozen in a tank at New- 

 castle-on-Tyne, were sent up to me by rail. They were 

 produced in the completely frozen state at the lecture, and 

 by careful thawing many of them were restored to perfect 

 life. At my Croonian lecture on muscular irritability after 

 systemic death, a similar fact was illustrated from frogs. 



