CELLOIDIN SACS 359 



one end of a gelatine capsule and allow it to cool 

 (Fig. 185). 



3 . Remove any gelatine from the lumen of the tube 

 with a heated platinum needle; paint the joint between 

 capsule and tube with moderately thick celloidin and 

 allow to dry. 



4. Dip the capsule into a beaker containing thin 

 celloidin, beyond the junction with the glass and after 

 removal rotate it in front of the blow- 

 pipe air blast to dry it evenly. Repeat 



these manoeuvres until a sufficiently thick 

 coating is obtained. 



5. Apply thick celloidin to the tube- 

 capsule joint, the opposite end of the cap- 

 sule, and the line of junction of the cap- 

 sule with its cap ; dry thoroughly. 



6. With a teat pipette fill the capsule 

 (through the attached tube) with hot 

 water, and stand the capsule in a beaker 

 of boiling water for a few minutes to 



melt the gelatine. Making celioidin 



7 . Remove the solution of gelatine from capsules. 

 the interior of the celloidin case with a pipette. 



8. Fill the sac with nutrient broth and place it, 

 glass tube downward, in a tube containing sufficient 

 sterile nutrient broth to cover the sac to the depth 

 of i cm. Plug the tube and sterilise in the steamer 

 in the usual manner. 



9. To prepare the sac for use, empty it out of the 

 broth tube into a sterile glass dish. 



10. Grasp the tube near its junction with the sac 

 in the jaws of sterile forceps, and with a teat pipette 

 remove sufficient of the contained broth to leave a 

 small space in the sac. Introduce the inoculum in the 

 form of an emulsion by means of another pipette. 



11. Still holding the tube in the forceps, draw it 

 out and seal off near the sac in the blowpipe flame. 



