SLEEP. 



697 



and was waiting in quiescence for its com- 

 mencement, the expectation alone was suffi- 

 cient to induce the sleep. When the patient 

 had no such expectation, all attempts to pro- 

 duce the sleep, that have come to our know- 

 ledge, have completely failed. Hence we are 

 strongly inclined to the belief that the rela- 

 tion between the mesmeriser and the som- 

 nambulist is one of a purely mental character, 

 and not the result of any new physical power. 

 With regard to what have been termed the 

 " higher phenomena" of mesmerism, we be- 

 lieve that without regarding them as the 

 result of intentional deception, most of them 

 are capable of receiving a very simple expla- 

 nation on the principles already laid down, 

 namely, that in the state of somnambulism 

 the senses, or some of them, are often en- 

 dowed with a wonderful acuteness, which 

 causes the mind to be acted on by impressions 

 that might be affirmed to be too faint to be 

 perceived ; and that these impressions will 

 suggest trains of thought, and give rise to 

 respondent actions, which are frequently of a 

 kind that the will could not produce. As to 

 the reality of the so-called clairvoyance, re- 

 peated personal examination has led us to a 

 negative conclusion. The sources of fallacy 

 arising from the causes we have mentioned, 

 as also from the tendency on the part of the 

 bystanders to afford assistance by asking 

 " suggestive" or " leading questions," and 

 from their disposition to interpret the least 

 shadow of a resemblance into a complete 

 coincidence, are such as greatly to diminish 

 the wonder that a firm belief in the reality 

 of these phenomena should be entertained 

 by many persons of excellent judgment and 

 great discrimination and acuteness as to all 

 ordinary matters. 



A state in most respects corresponding 

 with natural somnambulism is frequently in- 

 duced by the inhalation of ether, chloroform, 

 and other anesthetic agents. Instead of being 

 completely comatose, the patient, though quite 

 unconscious of pain, may be awake to ex- 

 ternal impressions received through some of 

 his organs of sense, so as during an operation 

 to obey the directions given him in order to 

 facilitate its performance ; and yet he shall be 

 completely unaware of what has taken place 

 when the effects of the anaesthetic agent have 

 gone off. But even the sense of pain may 

 not be extinguished, and the patient may 

 scream and struggle even more violently than 

 in the waking state ; and yet the whole is 

 subsequently forgotten, or is remembered only 

 as a troubled dream. It was further to be 

 noticed that, during the employment of ether, 

 the state of the nervous system induced by it 

 appeared to be much influenced by the pre- 

 vious degree of confidence entertained by the 

 patient as to its results. The more potent 

 action of the chloroform, however, has pre- 

 vented this influence from being so apparent. 

 ( W. B. Carpenter.) 



SMELL. The sense through which we 

 take cognizance of odours. 



Of the nature of odorous emanations no- 

 thing is certainly known. They are generally 

 supposed to consist of material particles of 

 extreme minuteness, detached from the odor- 

 ous body, and dissolved or suspended in the 

 air. This idea derives its chief support from 

 the facts that most odorous substances are 

 volatile, that is, their loss of weight, when 

 exposed to the air, shows that their particles 

 really diffuse themselves through it, that 

 most strongly odorous substances are ex- 

 tremely volatile and that circumstances which 

 increase the volatility of such substances also 

 augment their odorous powers. These gene- 

 ral statements, however, are not without their 

 exceptions. Thus, in the first place, we do 

 not find that many gaseous substances are 

 truly odorous ; the pungent, irritating qualities, 

 -by which many of them are distinguished, not 

 being perceived through the sense of smell 

 but through that of touch. Again, although 

 it is true that a great number of volatile 

 liquids are odorous, the strength of their scent 

 bears no constant proportion to their respec- 

 tive volatility ; and water, which is so con- 

 stantly diffused through the air, has no odor- 

 ous property. And with regard to solids, 

 we find that although some of those which 

 are most strongly odorous are also volatile 

 (such as camphor), yet this is not by any 

 means universally the case ; for it has been 

 proved by experiment that no diminution in 

 weight can be ascertained to take place in 

 musk or amber, although they have been 

 freely exposed to the atmosphere for many 

 years, and have imparted their perfume to an 

 almost incalculable volume of air. These 

 considerations have led some philosophers to 

 suppose that odorous emanations are not 

 material, but dynamical : in other words, 

 that the impressions made upon our olfactory 

 organ do not result from the contact of dif- 

 fused particles detached from the odorous 

 body ; but tKat they are effected by a change 

 propagated through the atmosphere or other 

 medium, in the same manner as sound is pro- 

 duced by undulations that originate in the 

 sonorous body, and are transmitted onwards, 

 through some material medium, to the organ 

 of hearing. There are strong objections, how- 

 ever, to this hypothesis. In the first place, 

 we find that odours are not perceived unless 

 the air, gas, or liquid in contact with the 

 olfactory surface is, or has been, in direct 

 continuity with the odorous body ; the inter- 

 position of any substance which prevents the 

 actual passage of the odoriferous medium 

 being sufficient to prevent the transmission of 

 the odour. This is by no means the case in 

 regard to sound, or to any other agent that is 

 known to be dynamically propagated ; for we 

 find many substances which are capable of 

 conducting these agents, that is, of transmitting 

 their influence through unlimited spaces ; and 

 this may be accomplished in spite of any 

 number of interruptions in their continuity, 

 provided the chain of conducting substances 

 be complete. Thus, sonorous vibrations may 

 be transmitted from air to liquids, from liquids 



