SYRINGES 



167 



In Roux's modification the glass barrel is narrowed below and ground so that 

 the needle is fitted directly on to it. The plunger can be freely withdrawn or 

 inserted since the tube is merely fitted above with a plug. 



Malassez's syringe. There are several patterns of this syringe. The only ones 

 which can be recommended are those in which the plunger consists of a mixture of 

 india-rubber and asbestos, or of "fibre," 

 a combination of cellulose and rubber. 

 The lower end is narrowed and ground and 

 the needle fitted on to it by means of a 

 "' fibre " washer. 



Metal plunger syringes. In these forms 

 the elastic plunger is replaced by a rigid 

 piston consisting of an accurately calibrated 

 metal rod, the body itself being an hollow 

 metal cylinder. These syringes soon de- 

 teriorate and are inconvenient in that the 

 liquid within them is not visible. 



B. Patterns recommended for use. 

 Roux's syringe (fig. 134). For serum- 

 therapeutic inoculations, Roux devised 

 a syringe of 20 c.c. capacity with a 

 plunger made of some rubber pre- 

 paration. The needle is connected to 

 the nozzle of the barrel by a piece of 

 rubber tubing about 10 cm. long. This 

 arrangement allows the injection to be 

 forced into the tissues without the 

 risk of detaching the needle. Before 

 sterilizing the syringe be careful to 

 loosen the upper socket to leave the 

 glass barrel room to expand, and so 

 prevent it being cracked. 



Debove's syringe (fig. 135). In the 

 author's opinion Debove's syringe is 

 better than Roux's. It is both easy 

 to manipulate and easy to sterilize : it 

 is solid and perfectly water-tight and 

 can be used for all sorts of inoculations. 



The syringe consists of a glass tube 

 held between two metal sockets by 

 means of a movable metal armature 

 which is entirely distinct and controlled by a lever. The barrel is accurately 

 calibrated and the syringe is made water-tight with asbestos washers. 



The lower metal socket has a conical extension on to which the needle 

 fits either directly or through an india-rubber connexion. 



The plunger consists of asbestos rings held between two metal discs. The 

 piston rod carries a screw which allows the pressure on the asbestos rings 

 forming the plunger to be varied so that the play of the plunger can be 

 regulated. 



The syringe is easily taken to pieces by raising the lever ; this relaxes 

 the lateral stays which can then be disconnected and the sockets taken off. 



All parts of the syringe are made to a standard pattern, so that broken 

 parts can be replaced without sending it to the maker to be repaired. The 

 syringe is made in several sizes to hold from 2-100 c.c., those ordinarily in 

 use being of 2, 10 and 20 grams' capacity. 



FIG. 134. Roux's 

 syringe. 



FIG. 135. Debove's 

 syringe. 



