DROP-BOTTLES MOUNTING THIN SECTIONS 



477 



are best kept in wide-mouthed cupped jars, the liquid being taken 

 out on a pointed glass rod, cut to such a length as will enable it 

 to stand in the jar when its cap is in place. Great care should be 

 taken to keep the inside of the cap and the part of the neck of the 

 jar on which it fits quite, clean, so as to prevent the fixation of the 

 neck by the adhesion between these two surfaces. Should such 

 adhesion take place, the cautious application of the heat of a spirit- 

 lamp will usually make the cap removable. In taking out the 

 liquid care should be taken not to drop it prematurely from the rod 

 a mischance which may be avoided by not taking up more than it 

 will properly carry, and by holding it in a horizontal position, after 

 drawing it out of the bottle, until >its point is just over the slip or 

 cover on which the liquid is to be deposited. 



A bottle for use with reagents, enabling the operator to pour out 

 < )iily the quantity he desires, is invaluable. Small capped and stoppered 

 bottles, the stoppers of 

 which are tubes, and the 

 well-fitting caps of which 

 prevent evaporation, arc 

 very valuable for aqueous 

 and thin fluids. We illus- 

 trate this bottle in fig. 404. 

 All that is needful is to 

 take the bottle, with the 

 cap off, in the warm hand, 

 and by slight expansion a 

 drop or more as required 

 is exuded. These bottles 

 are easily procurable. 



But we like still better 

 the small German bottles, 

 shown in fig. 405, contain- 

 ing about 30 grammes, in 



which two deep grooves are cut on opposite sides of the stopper, so 

 arranged that by giving the stopper half a turn one groove is 

 connected with a hole in the neck of the bottle : this will be seen at 

 a in fig. 405 ; the air travels down this groove, and by inverting the 

 bottle the fluid enters the other groove of the stopper and finds its 

 way to a third groove cut in the inside of the neck and extending to 

 the lip. The figure shows the bottle complete. 



Mounting Thin Sections. It is customary to recommend the use 

 of ' section lifters ' in order to raise delicate sections out of the fluid 

 in which they finally are placed into the position in which they are 

 to be mounted. For very large sections they are probably essential ; 

 but from personal experience, supported by the most accomplished 

 histological mounters of our time, we believe them to be adverse to, 

 rather than promotive of, good section-mounting. One of the 

 many patterns recommended is shown in fig. 406, where it will be 

 seen that one end of the * lifter ' is perforated, for the purpose of 

 drainage, and the other is plain. 



The present writer cannot endorse the recommendation of this 



FIG. 404. 

 Expansion drop- 

 bottle. 



FIG. 405. 

 (TCVDUUI drop-bottle. 



