Med. Prop. and Action. Amylene was introduced as an anAesthetic in 1856 by the late Dr. Snow,t with whom it continued to be a favourite anAesthetie to the period of his death, in 185S. It was considered by him to possess the following advantages over Chloroform and Ether: - 1. The greater ease with which it could be breathed, owing to its entire want of pungency and irritating property. 2. The greater readiness with which absence of pain is obtained, with less profound coma than usually accompanies Chloroform or Ether. 3. The greater promptitude with which patients generally recover from its effects. 4. The greater infrequency of vomiting. 5. The less amount of rigidity and struggling during its operation; and, 6. The small amount of headache which results from its use.
* Guy's Hospital Reports, 1S62, p 293. On AnAesthetics, pp. 373 - 419.
From Dr. Snow's experiments on animals, it appears that Amylene, like Chloroform, is capable of causing sudden death by over-narcotism of the heart, and paralysis of that organ; but he is of opinion that it is more difficult to cause this kind of sudden death with Amylene than with Chloroform. Two fatal cases occurred in Dr. Snow's practice with this agent; and he attributes the fatal result in each case to the patient taking into his lungs air containing 30 per cent. of the vapour of Amylene; whilst, as far as the safety of the patient is concerned, the amount should in no instance exceed 15 per cent. This was probably due to the variation in its boiling point (86° to 115o F.), and to the fact that different specimens do not always possess the same amount of volatility. This, it must be owned, is a great objection to its use; and its ready volatility, even at ordinary temperatures, renders it a dangerous, even if not an unavailable, anAest letic in tropical countries. In these cases, Or. Snow employed a regular Chloroform inhaler; but he suggests that in future cases it should be administered from a bag or balloon, putting into it so much of the liquid as will make 15 per cent of vapour, when the bag is filled up with air. In this manner the variability in the boiling point of Amylene can have no influence whatever on the amount of vapour which the patient breathes; and if the vapour be breathed over again within certain limits, there will be a great saving in the amount of Amylene consumed.
Dr. Snow adduces the evidence of many eminent men in favour of this agent, and in conclusion expresses his opinion that it ought to be placed between Chloroform and Ether in respect to its comparative safety by the ordinary methods of administration, but that by breathing it from a bag, in the manner advised above, it would be absolutely safe so long as the right quantities were put into the bag.
It is only right to add that other practitioners have not formed so high an estimate of the value or safety of Amylene as Dr. Snow; indeed, the French Academy of Medicine (apparently on insufficient grounds) has condemned its employment as dangerous. Still, it must be admitted that any statement coming from so trustworthy and experienced an observer as Dr. Snow demands every respect and attention.