286 Physiology. 



cotic poison, resulting in a deep sleep characterized by 

 great contraction of the pupils of the eyes, insensibility, 

 and death. 



Chloroform. Chloroform is a liquid that readily evapo- 

 rates. Its vapor, mingled with air, is inhaled to produce 

 unconsciousness and loss of sensibility. It is one of the 

 most valuable of modern discoveries for use in surgical 

 operations. When used repeatedly, to induce sleep, it 

 becomes a habit hard to break, for, like other narcotics, 

 it produces such an effect on the system that there is a 

 craving for it. It should be used only by physicians. 



Ether. The use of ether is about the same as that of 

 chloroform. Ether is considered safer than chloroform, 

 as the latter occasionally causes death by paralyzing the 

 heart. In some cases chloroform is preferred. Both 

 ether and chloroform produce death if too large an amount 

 is taken. 



Nitrous Oxide. This gas also produces loss of sensi- 

 bility, though often not so complete a loss of conscious- 

 ness. Its effects soon pass away. It is therefore more 

 suited to very short operations, such as the extraction of 

 teeth, and is much used by dentists. 



Chloral Hydrate. This drug is frequently, but incor- 

 rectly, called chloral. It is a powerful sleep-producer and 

 lowers the action of the brain and spinal nerve centers, 

 and, to a limited extent, is an anesthetic. It is very useful 

 in fevers accompanied by brain excitement, and in convul- 

 sions. Its effects in producing sleep have led to its use 

 by individuals without a physician's prescription, and often 

 with fatal results. No drugs of this class should be used 

 except under the advice of a physician. 



