330 APPLIED IMMUNOLOGY 



tion is to triturate 0.6 gramme of salvarsan in a sterile 

 mortar with twenty-three drops of fifteen per cent, sodium 

 hydroxide solution, then to dilute with distilled water to the 

 desired volume. 



More recently intramuscular injections have been exten- 

 sively made with simple suspensions of salvarsan and neo- 

 salvarsan in oils, 1 : 10 dilution, such as sesame, olive 

 sweet almond and paraffin. Certain pharmaceutical labora- 

 tories market the neutral, water-free solidified fat suspen- 

 sions, liquid at body temperature, in sterile ampoules, 

 requiring merely a syringe for their administration. 



The neutral suspension, at one time largely used, both in- 

 tramuscularly and subcutaneously, at present enjoys a very 

 restricted emplo3"ment. It is prepared by triturating care- 

 fully 0.5 or 0.6 gramme of salvarsan with eight or ten drops 

 of fifteen per cent, caustic soda solution in a sterile porcelain 

 dish. To this is added at first drop by drop with constant 

 trituration the required quantity of sterile water (5 to 

 10 c.c). The fine suspension thus produced is tested exact- 

 issme with litmus paper for neutral reaction, and a drop 

 of the soda solution or hydrochloric acid added in accord- 

 ance with the reaction. 



The upper outer quadrant of the gluteal region is the 

 most desirable locality for intramuscular injection, by 

 virtue of comparative freedom from nerves and blood-vessels 

 (Fig. 59). The vicinity of the sciatic nerve must be care- 

 fully avoided. The injection should be given deeply and 

 slowly, thereby obviating hemorrhage and rupture of the mus- 

 cular tissue. The skin is conveniently disinfected at the site of 

 injection by three to five per cent, tincture of iodine. After 

 injection the fluid is distributed as widely as possible by 

 careful massage, and the needle puncture sealed with col- 

 lodion. In sensitive patients the area to be injected may be 



