May 21, 1920] 



SCIENCE 



503 



the vital processes of the cells are partly inter- 

 fered with.^' 



3. To anesthetize the area supplied by a 

 given nerve, it is only necessary to inject a 

 sufficient amount of solution directly into the 

 nerve trunk. This often effects a great saving 

 of labor and material. The larger nerve 

 trunks were first blocked in this manner by 

 Dr. Harvey Gushing, of Boston. 



4. Anesthetics are occasionally injected im- 

 der the sheath of the spinal cord itself. 

 Spinal anesthesia vs^as introduced in 1885 by 

 Dr. J. Leonard Corning, of New York, in the 

 same year in which Dr. Halsted, of Johns 

 Hopkins, began his pioneer work in cocaine 

 surgery. Many of you may recall that in the 

 closing years of the last century a substance 

 known as stovaine, belonging to the orthoform 

 group, was widely heralded in comiection with 

 spinal anesthesia. 



5. To produce venous anesthesia an area is 

 made bloodless by tight bandaging and the 

 anesthetic solution injected backwards into 

 the vein which ordinarily transports blood 

 away from that area. 



Certain substances have been tested as ad- 

 juvants, to be added to local anesthetic solu- 

 tions. Among these epinephrin has been 

 found extremely valuable and is universally 

 employed, while sodium bicarbonate and potas- 

 simn salts are deserving of mention. 



For terminal anesthesia procaine is injected 

 in solution with epinephrin, the active prin- 

 ciple of the adrenal gland. A concentration 

 of 1-100,000 of the latter suffices to blanche 

 the tissues by contracting the small blood 

 vessels with which it comes in contact. This 

 serves two useful purposes, to make the oper- 

 ation practically bloodless and to prevent any 

 rapid carrying off of the drug into the circu- 

 lation. 



15 Terminal used in combination with general an- 

 esthesia is believed to rdb the latt«r of some of its 

 dfisadvantages, for while the patient, narcotized by 

 ether, chloroform, or nitrous oxid, does not per- 

 ceive the afferent nerve impulses set up by surgical 

 procedures, these reach the central nervous system 

 nevertheless and may contribute to the untoward 

 condition known as ' ' shock. ' ' Local anesthesia 

 tends to prevent the transmission of such impulses. 

 (Crile.) 



Sodium bicarbonate as an adjuvant to local 

 anesthetics was suggested by Gros^'' (1910), 

 who believed that bringing the alkaloids into 

 their basic forms, would aid them in pene- 

 trating the tissues. Dr. Torald Sollmann,^' 

 of Cleveland, has found that it does in fact 

 enhance the action of such alkaloids when 

 they are applied to mucous surfaces. On the 

 other hand, he denies that it has any special 

 value in terminal anesthesia. 



With regard to potassium salts it may be 

 mentioned, that Hoffmann and Koclunann^^ 

 (1912) claimed that potassium sulphate pow- 

 erfully potentiates the action of procaine in 

 intracutaneous anesthesia. Dr. Sollmann's re- 

 sults conflict with this claim as do also the 

 results of a niunber of unpublished experi- 

 ments which I have made in association with 

 Professor Bernard E. Read, of Peking. In 

 short, salts of potassium, which in fairly high 

 concentration produce a certain amount of 

 intracutaneous anesthesia, when given in com- 

 bination with such a substance as procaine, 

 yield a result representing merely the al- 

 gebraic sum of the results obtained by giving 

 the two substances separately. 



The theory of action of local anesthetic 

 drugs has not yet reached a satisfactory state. 

 Gros believes that their anesthetic power runs 

 parallel to the amount of free base which is 

 present and that esters such as cocaine and 

 procaine must therefore be hydrolyzed before 

 anesthesia can take place. The extent of the 

 anesthesia would therefore depend upon the 

 degree of hydrolysis of the drug taking place 

 in the tissues. The new findings concerning 

 substances of the benzyl alcohol series show 

 that phenolic alcohols contain all that is 

 essential to local anesthetic action and that 

 for introduction into the field of operation it 

 is not necessary to mask them as esters. 



Exactly what happens to the nerve tissues 

 when brought into contact with a local 

 anesthetic drug has not been determined. 



16 Gros, O., Arch. f. exp. Pathol, u. Pliarmakol., 

 LXIII., 1910. 



IT Sollmann, T., /. A. M. A., January 26, 1918, 

 p. 216. 



IS Hoffmann, A., and Koohmann, K., D. M. W., 

 1912, 38, 2264. 



