BY N. A. COBB. 165 



The suction-capsule is made from thin glass tubing of two to five 

 millimeters external diameter. A capsule adequate for experiments 

 on lower animals is easily made. Connect an ordinary blow-pipe 

 with a filled air-bag and produce a narrow oxidizing-flame by 

 sending a blast fiom the blow-pipe through the flame of a small 

 alcohol lamp. Heat the glass tubing successively in two places 

 and draw it out into the form shown in Fig. 5. The length of the 

 central capsule, s, should not much exceed twice its width. Now 

 break off the tubing at one end of the capsule and heat that end 

 in the blow-pipe flame until the aperture becomes minute, and 

 follow this operation by heating and drawing out the narrow tube 

 at the other end of the capsule into the form shown at t, Fig. 6. 

 The glass at t will remain tubular. Suppose the minute aperture 

 at ?//, Fig. 6, to be stopped with glue. Then if suction be exerted 

 at r and while the suction is being exerted the tube at t be melted 

 in a tine-pointed blowpipe flame, the capsular portion will be 

 severed from the remainder of the tube shown in Fig. 6, and will 

 constitute what I call a suction-capsule. (See Fig. 7.) Such a 

 capsule contains a partial vacuum, and has the power under ap- 

 propriate conditions of exerting suction. This characteristic 

 property is soon observed if the cap.sule be immersed in water. 

 The plug of glue soon dissolves and water is then drawn into the 

 capsule in quantity proportional to the previous exhaustion of the 

 air. For instance 



a capsule which weighed ... ... ... 108 mg. 



on being filled with water weighed ... ... 230 mg. 



Hence the capsule was capable of holding ... "122 cc. 



After partial exhaustion of the air and immer- 

 sion in water the weight was ... ... 150 mg. 



Hence the water sucked in weighed ... ... 42 mg. 



In other words this suction-capsule when immersed in water 

 sucked itself about one-third full. This completely illustrates the 

 mechanical action of the capsule and it now only remains to say a 

 word about the manner of its use. It is made the vehicle for 

 conveying to the stomach of animals, man included, the eggs of 

 entozoa. On reaching the stomach the capsule takes in gastric 



