A third method of inducing regional anæsthesia--first recommended by Hackenbruch--which is worth mention, is by the production of a ring of infiltration around a peripheral part, such as a finger, or around and underneath a tumour. By this means the nerve fibres are caught up by the anæsthetic and their conductivity interrupted as they enter the area to be operated upon. In dealing with such conditions as a large lipoma, or an umbilical hernia, it may be possible to avoid the use of an excessive amount of anæsthetic solution by employing this method. Methods of Application of Infiltration and Regional Anæsthesia. It is sometimes stated that local anæsthesia should be limited to small and superficial operations, but with a knowledge of anatomy and of the correct technique, there are few operations which the surgeon cannot undertake with this form of anæsthesia. If we remember that the mortality from the anæsthetic is practically nil, it is obvious that it is often the duty of the operator to give the patient the choice of local anæsthesia. In urgent conditions in which the administration of a general anæsthetic would be attended with great danger, it is often a life-saving measure. Either infiltration or regional anæsthesia may be used alone; in some cases it is convenient to combine the two methods. Operations on the Upper Extremity. Regional anæsthesia is sometimes employed in operations on the upper extremity in conditions, such as diabetic gangrene or advanced cardiac disease, where a general anæsthetic is contra-indicated. In similar conditions in the lower extremity, spinal anæsthesia is usually preferred, though it is quite possible to anæsthetise the lower limb by blocking the sciatic, femoral, and lateral cutaneous nerves with a local anæsthetic. Crile lays great stress on the blocking of nerves with a local anæsthetic during operations on the limbs as a means of preventing shock, even where a general anæsthetic is being employed. The effect of the local anæsthetic is to prevent the impulses which produce shock from passing up to the higher centres. Only those methods which are applied to the upper extremity need special description.