Page:The Indian Journal of Medical Research, 1920.djvu/19

Rh sterile filtered water. The area is then dried and covered with a sterile cloth. No antiseptics are used in the cleansing of the calf's skin.

Vaccination is carried out, with an ordinary scalpel, dipped in the seed lymph; the scalpel is drawn lightly across the skin, making long, parallel incisions, into which the seed lymph is introduced by the back of the scalpel. The incisions should not be deep enough to draw blood, otherwise the resulting vesicles will not be so well formed. The lines of incisions are spaced about 3-8th of an inch apart. The vaccinated area is dried, by the aid of an electric fan, before removal from the table. The calf is then taken to the inoculated calves' stable, where it is kept for 5 days, while the vaccinia is maturing. Clean cloths are tied over the vaccinated part and renewed as required. Glycerine is applied to the developing vesicles 48, 72 and 96 hours after vaccination. This tends to prevent the premature drying of the vesiculation and helps its development. The calf is kept as dry and clean as possible, during this period.

At the end of 120 hours the vaccinated calves are again brought on the table and carefully washed with soap and warm water and sterile water and the area covered with a clean cloth. When thoroughly dry, the vesicles are inspected and a note made as to their quality. The quality is graded as good, fair or trial or rejected as unfit for collection. The pulp from those in good or fair class is not further tested as regards potency before issue. That from the 'Trial' class is tried on children before it is declared fit for issue.

The percentage of 'Rejected' calves is shown in the following table for a number of years:—