Page:The Indian Journal of Medical Research, 1920.djvu/30

232 chloroform then blown off. This portion was labelled E. The five lymphs, now prepared as above, were examined by plating on agar and colonies counted.

The five lymphs, A, B, C, D and E, were then divided into three parts and labelled as follows : —

A 1, A 2, A 3, B 1, B 2, B 3, and so on.

The A 1, B 1, CI, D 1 and E 1 were placed in the incubator at 37° C.

A 2, B 2, etc., were kept at room temperature, average about 24° C.

A3, B 3, etc., were placed in cold-store, average temperature about 5° C.

After seven days' storage, as above, calves were vaccinated with each of these emulsions in separate lines of 3" in length, so that calf No. 681 had three lines, representing the A series, three lines of B series, etc., in all 15 lines. This was repeated on two other calves. The calves were examined after 120 hours and the resulting vesiculation carefully compared and recorded; vide Appendix B.

The emulsions were then returned to the incubator, room and coldstore, as before, and kept for a further seven days and again a series of calves was vaccinated in a similar way and the results recorded. This was again repeated in further series of calves after 21 and 28 days' storage, but those emulsions, which gave no vesiculation, after 21 days, indicating the death of the virus, were not carried on further.

A study of the results, recorded in the Table, will show the very definite effect of temperature on the vitality of the vaccine principle. Whatever the diluent used, the virus is much weakened, and in many cases killed outright, after 14 days at blood heat. The very marked lethal effect of 1 per cent phenol at 37° C. is noticeable. Noguchi4 found that his strain of vaccine was more resistant in dilutions of .5 to 1 per cent phenol than in 40 per cent glycerine. My experiments do not confirm this; in 40 per cent glycerine the virus retained its vitality almost unimpaired for seven days at 37° C. and was still alive after 28 days. In 1 per cent phenol, on the other hand, the virus was killed after seven days and was barely alive after 14 days in 5 per cent phenol.

The effect of heat on the lymph, which was prepared in saline solution, is very unexpected. The virus was killed after seven days at 37° C, except for one or two points which survived. The lethal effect must be accounted for by the marked multiplication of extraneous organisms which took place in the case of the saline-diluted lymph. The bacteriological results have not been included in the Table but are being worked out separately