_Mode of Employment._--A fresh solution of the drug should be made each time its use is called for, by dissolving a tabloid weighing half a grain in 5 minims of distilled water. Half of the solution should be injected into the gum on each side of the alveolus. The gum being such a dense tissue, the solution should be injected slowly, otherwise the bulk of it will escape by the side of the needle into the mouth. As there is always a tendency for this to happen even when the solution is slowly injected, it is well to keep a finger of the left hand pressed on the gum where the needle is inserted. Speaking personally, I usually occupy about eight minutes over the injection, and wait for four or five minutes after its completion before operating. As a local anæsthetic I have generally found cocaine satisfactory, so far as its anæsthetic properties are concerned, but the occasional appearance of toxic symptoms, especially in those of feeble health, should not be lost sight of. Tropacocaine has been recommended as possessing the anæsthetic properties of cocaine without giving rise to toxic effects, but in practice I have not found these statements fully borne out. _Toxic Effects._--The administration of cocaine, especially if given in large doses, may be followed by well-marked toxic effects of which the following are cited by Dr. Hewitt.[4] “Headache; vertigo; pallor; a cold, moist skin; a feeble, slow, or rapid pulse, becoming imperceptible in grave cases; incoherence of speech; nausea; vomiting; unconsciousness; trismus and other muscular spasms; epileptiform attacks; dilated or unequal pupils; and disturbances of respiration, culminating in dyspnœa and asphyxia.” The treatment of cocaine poisoning should be directed first to restoring the circulation by the administration of a rapidly acting stimulant, such as sal-volatile, brandy, or the hypodermic injection of ether. The patient should be placed in the horizontal position, and the respiration watched for; should this tend to fail, artificial respiration must be immediately resorted to. (_b_) =Freezing Agents.=--This group includes such preparations as _chloride of ethyl_, _coryl_ (a mixture of chloride of ethyl and chloride of methyl in such proportions that the mixture boils at 0° C.) and _anestile_. Generally speaking, the anæsthesia produced is by no means satisfactory, and to use them to the greatest advantage, attention must be given to the following points:-- (1) The gums must be well dried, and as far as possible all neighbouring regions, such as the cheeks or tongue, protected by napkins or other suitable material. (2) The gums must be thoroughly frozen before commencing to operate. (3) The extraction must be carried out as quickly as is consistent with thoroughness. (4) If possible the spray should be continued during the operation. (5) Too great a jet should not be used.