LOCAL AN.ESTHESL\ BY INFILTRATION. 6g 



little blister previously produced. This is quite painless, as the area 

 has now become insensitive. A further blister is thus produced, and 

 the operator proceeds in the same way until a chain of blisters is 

 formed covering the entire length of the incision presently to be made. 

 Each of these points of artificial oedema is anaesthetic. The method 

 succeeds, not only in the case of skin and mucous membranes, but in 

 serous and synovial membranes, muscles, nerves, and the periosteum. 

 Even bones and the bone medulla can be rendered anaesthetic by 

 subperiosteal injections. Deeper-l3ang tissues can, of course, only be 

 rendered angesthetic after the more superficial have been so treated. 

 The condition persists for fifteen to twenty minutes ; should an 

 operation last longer the process must be repeated. In preparing for 

 the insertion of sutures for instance, the needle of the syringe is passed 

 from the cut surface towards the skin, so that the path which the 

 suture needle will afterwards take is rendered cedematous. The bleed- 

 ing from tissues thus rendered cedematous is remarkably slight ; on 

 incision the injection fluid is first of all discharged without admixture 

 of blood, then little points of bright arterial blood appear in the fluid 

 from the wound. 



According to Schleich the injection of distilled water also induces 

 local anaesthesia. A solution of "2 per cent, chloride of sodium sets 

 up local anaesthesia without previous hyperaesthesia ; 3 per cent, 

 solutions of sugar produce more or less pronounced anaesthesia. 

 Pietro Ghisicui has experimentally studied at the Turin Veterinary 

 School the results obtained by the above-mentioned formulae, and by 

 distilled and sterilised water. 



The quantity of cocaine solution or of distilled and sterilised water 

 employed varied ; generally he used from 2^ to 16 drachms of the 

 strong solution, 3 fluid ounces of the moderately strong solution, 

 4i fluid ounces of the weak solution, instead of i^ to 4^ fluid ounces 

 of water. He noted a fleeting hyperaesthesia during the operation, 

 the tissues became turgescent, infiltrated, cedematous, and anaemic. 

 The oedema produced by the water and by the solution of Schleich 

 disappears after eight or nine hours. The vitality of the tissues is 

 unaltered, and cicatrisation takes place regularly. Complications, 

 such as stupefaction, nervous or functional troubles, etc., have not 

 been observed. 



From twenty-two experiments made with water, and the same 

 number with Schleich's solution, the author draws the following 

 conclusions : 



Anaesthesia by infiltration should be more common in veterinary 

 practice. Schleich's method is very useful, practical, and cheap. 



