Page:The Indian Journal of Medical Research, 1920.djvu/27

R. W. Fisher. 229 on duty in the Presidency proper and one in Sind, so that a very efficient supervision of the vaccinating staff is maintained. Further, it must be emphasised, in considering these results obtained with Belgaum lymph, that vaccination work is carried on throughout the hot season and not only in the cold weather, as obtains in some parts of India. A very severe test is thus thrown on the potency of the lymph, as, in many of the northern districts of the Presidency, very high temperatures are recorded during the hot months of the year, and the heat in Sind during the summer is notorious, shade temperatures of over 120° F. being often recorded.

The apparatus used:—

The apparatus consists of a water blast pump A, which is connected to a steady head of water, so that pressure varies as little as possible. The pump is connected by rubber tubing to a large empty bottle B, which receives any water accidentally driven over from the pump. The current of air then passes through an air filter C, consisting of a brass tube filled with cotton wool, the whole being sterilized in the autoclave. After passing through the filter, the air enters the gas washing bottle D, containing pure chloroform ( B. W. and Company, anaesthetic ). The chloroform-saturated air is now led through a Woulff's bottle E, containing dry sterile sand designed to interrupt any chloroform which might be driven over by accident. The air then passes into a chest F, which contains the tubes of lymph. This chest has a double jacket, the inner, made of brass, is so arranged that ice can be introduced into the box, ice cold water circulates round the jacket and a temperature of 10° C. can be maintained. The tubes G are large 1 1/4 bore and arranged in series, with rubber tubing, so, that the air is bubbled through each tube in succession and escapes at the end of the series through a tube led outside the box at H. At the beginning of the series an empty tube intervenes, so that any condensed chloroform is retained and does not gain access to the lymph-containing tubes. One-third of each tube is filled with lymph, and the glass tube, carrying the entering air, passes down close to the bottom of the tube, which causes the chloroform-saturated air to bubble up through the lymph and pass on to the next tube of the series. The pressure of air is so regulated that the air bubbles gently through the lymph without-