1282 



Journal of Applied Microscopy 



i^^ 



A Method for Injecting Small Vessels. 



When injecting vessels too small to use the ordinary removable cannulas 

 usually provided with injection syringes, it is customary to employ a small glass 

 cannula with rubber-tube connections. This has the great objection that in order 

 to avoid forcing air into the vessel it is necessary to fill the apparatus before it 

 is inserted and tied. When one then attempts to insert the cannula it is very 

 difficult to prevent the injecting mass from coming out at the tip, getting into the 

 surrounding tissues, and so obscuring things that it is next to impossible to see 

 what one is about ; and so much time is usually consumed in the process that 

 the mass is apt to harden and clog the opening of the cannula. To prevent this a 

 clamp is usually placed upon the rubber tube, but even then it is far from satisfactory. 

 A modification of this, using the principle of the removable cannula, has been 

 found to give very satisfactory results. A piece of glass tubing of a little larger 

 diameter than would ordinarily be used is taken and drawn out to the 

 — c desired fineness, depending upon the size of the vessel for which it is 

 to be used. It is then cut oiT short so that it is much like a small 

 funnel (a). The tip is flared slightly in the ordinary way to prevent 

 the ligature from slipping. Another piece of tubing is now taken 

 whose outside diameter is about the same as the inside diameter of 

 the other — one that will just slip within the other nicely — ^and is 

 drawn out slightly at one end and cut off so as to leave that end 

 somewhat tapering. A short piece of rubber tubing is drawn over 

 this tapering end (/?), so that when it is inserted into the upper end 

 of the cannula ( a) it makes a perfectly tight joint. A rubber tube from 

 the nozzle of the syringe leads to the other end (r) of the glass tube. 

 The cannula can now be inserted and ligatured. It should then 

 be filled with some of the injection mass, either with a pipette, or by 

 allowing it to drop in from the syringe. By using a small wire care- 

 fully it is possible to get practically all of the air out of the cannula 

 and to get it well filled with the mass. The rubber-covered end of 

 the tube can then be placed in the cannula and the pressure applied 

 to the syringe, care being taken to hold the joint together tightly. 

 This device has all the advantages of the regular injection syringe 

 over the glass cannula ordinarily employed, and is very simply and easily con- 

 structed. Leon |. Cole. 

 Zoiilogical Laboratory, University of Michigan. 



The thirty-second anniversary meeting of the New Jersey State Microscopical 

 Society occurred on March 2.5th. Mr. F. E. Ives of Philadelphia delivered an 

 illustrated lecture on that occasion, his subject being " The Kromskop and 

 Color Photography." J. A. Kelsey, Secretary. 



