24 



METHODS IN PLANT HISTOLOGY 



water. Shorter periods may be sufficient for some things, but 24 hours 

 will not do any damage even to the most delicate objects, and a shorter 

 time may be insufficient. 



Heavy objects which sink promptly may be placed in a Stender dish 

 or wide-necked bottle under a gentle stream of water. There is little 



danger in this method if the material is heavy 

 enough to remain at the bottom : the only ob- 

 jection is that much of the water does not 

 reach the bottom. Here is a better method: 

 tie a piece of cheesecloth over the neck of a 

 bottle ; slip over the water tap a rubber tube 

 with a piece of glass tube tied in the end, and 

 slip the glass tube through the cheesecloth 

 nearly down to the bottom of the bottle. The 

 washing will then be very thorough. A 

 method devised by Dr. Dudgeon is simple and 

 very efficient, especially for delicate materia 

 or objects which have a tendency to float. A 

 glass tube, 1 inch in diameter, is cut into 

 pieces 2f inches in length. The glass is then 

 heated to round off the sharp edges and, 

 while the glass is still very hot, one end is 

 flared a little, so that a piece of cloth can be tied over or fastened over 

 it with a rubber band. Bolting cloth or bolting silk is best because 

 water passes through it so readily. For flaring the ends of the tubes 

 a triangular piece of copper ^V i^^ch thick is very convenient (Fig. 13). 

 Heat the copper, cut the edges into a cake of beeswax, and turn the 

 instrument around a little in the end of the hot glass tube. Any num- 

 ber of these tubes can be placed in a jar without any danger of losing 

 material. 



Another method which we have found satisfactory is to put the 

 material into a tea filter, which can be got at the five-and-ten-cent 

 store. This is good for everything except filamentous forms which 

 stick in the little holes. Any number of the tea filters can be placed in 

 a jar and washed from a single water tap. 



Here is still another method: take a box about 6 inches wide, 18 

 inches long, and 4 inches deep ; bore |-inch holes in the bottom, and 

 into each hole put a piece of rubber tubing about 4 or 5 inches in length. 

 Pipettes can be fastened in the ends of these rubber tubes. Place the 



Fig. 13. — Instrument for flar 

 ing glass tubes. 



