With the paraffin may be boiled a number of test tubes. These after boiling one-half hour may be lifted from the boiling water with forceps. As they will be quite hot if they are held with opening downward the water will drain from them and their own heat will evaporate the few drops in the interior and they will be left dry. Into each test tube sufficient paraffin may be poured to fill a syringe and then they should be plugged with sterile cotton or corks which have been boiled. The test tubes containing the paraffin mixture may then be put away and when taken out at a later time for filling the syringe the paraffin may be melted by heat and poured into the sterile syringe or the paraffin may be boiled by holding the test tube over a Bunsen burner, or other heater. When paraffin boils the temperature of the boiling mixture is higher than that of boiling water but the boiling causes dense black smoke to be given off and this is objectionable in a closed room. Repeated boiling of paraffin causes it to discolor but this does not occur when the vessel containing the paraffin is placed in a water bath and the water around the paraffin container boiled. No smoking of the paraffin occurs when it is heated in a water bath and this means of sterilization is the most satisfactory though the first time the paraffin is sterilized it should be kept in the boiling water for a half hour. A softer mixture of paraffin, which may be used when in fear of the effects of the injection of the harder mixture, is made as follows: FORMULA NUMBER TWO. Paraffin, two ounces. White vaseline, eight ounces. Melt together and sterilize. This second paraffin compound is advisable when the operator is anxious to secure a plugging action with a mixture which will always be fairly soft, and which is less likely to be absorbed than plain sterilized white vaseline. Vaseline. The third compound is the sterilized white vaseline. It is probable that this agent is frequently absorbed in a comparatively short time but it has the valuable property of diffusing freely through the tissues so that it produces a more extensive reaction and when it is used in connection with the harder mixtures the operator may be more certain of securing an occlusive inflammation of the sac of the hernia and the more extensive production of connective tissues so that the parts separated to make way for the passage of the hernial sac are more certainly bound together. None of these mixtures are hard. If a portion of the mixture first described is secured under the arm for a half hour or held in the mouth for that length of time and it is raised to body temperature it will be found that it is comparatively soft. It is not a liquid and it is not likely to be absorbed, yet it is not a hard waxy mass.