The subject of anesthesia in the operative treatment of rectal diseases is one that is dependent in most instances upon the technical knowledge of the case under consideration and the dexterity of the operator. In other words, the correct diagnosis of a small fistulous tract will make it possible to operate under local anesthesia or nitrous oxide gas; whereas general anesthesia is required if the diagnosis is not positive, and when the operator does not know how much tissue he is to incise, or feels uncertain as to the complications. When only a single hemorrhoid is to be removed, local anesthesia in the form of cocaine or eucalypti will often suffice. When more than two hemorrhoids or an extensive fistula is to be operated upon, local anesthesia is not advisable, as the mere handling of the tissue soon causes the patient to resist treatment, and proper surgical technique becomes impossible. Ether or chloroform may be used in all extensive and prolonged operations for the relief of rectal diseases, and their relative value and dangers are so well known they need not be discussed.

Nitrous oxide and oxygen or laughing gas is an anesthetic which I think might be used by rectal surgeons in general with great satisfaction. In a limited experience with it when operating on hemorrhoids and fistula, I have not a single recollection that would tend to prove it anything but a safe and efficient anesthetic, and it seems to me that I should have used it oftener were it not that ether nsrcosis had become a habit. There is much less shock and depression with nitrous oxide gas than with ether or chloroform and the patient regains consciousness within a minute or two after the administration of the anesthetic is ended. Symptoms of vomiting and depression of the heart or respiratory centers seldom or never occur. Its use is also indicated in performing colostomy or in the closing of an artificial anus, the incision of fissures, the removal of hemorrhoids, the dilatation of the anal ring, or strictures, the removal of polyp and many other operations which do not require more than fifteen or twenty minutes to accomplish.

When we consider that laboratory investigations have shown conclusively that chloroform and ether impair phagocytes and produce anemia, rectal operations, which certainly are more liable to infection, require the best effort in this direction. Nitrous oxide gas does not interfere with phagocyte action so that the patient's resisting power against infection is not lowered, and the vital energy is conserved. The administration of citrons oxide is so pleasant that as a rule patients readily submit to an operation with the idea that it will not prove any more serious than the extraction of a tooth.

The best local anesthetics for rectal operations are cocaine, eucalypti, Stolypin, quinine and urea hydrochloride and liquid air. Cocaine and eucalypti should not be used in strengths greater than four per cent. not only on account of their poisonous qualities, but because anesthesia should always be produced with that strength. Ethyl chloride has been advocated for rectal operations, but I wish to condemn its use, as the freezing of the mucous membrane produces pain, and the pain after the incision of the tissue is again very severe.