W. H. GILBURT ON THE STAINING OP VEGETABLE TISSUES. 309 



in it for twelve hours without requiring the removal of any colour. 

 Experience also shows, that, as a rule, far better results are obtained 

 by the use of dyes of small intensity, although more time may be 

 required. 



I would therefore advise the use of the solution as given in the 

 earlier part of this paper. The object should be left in it till equally 

 stained, then remove from the dye into alcohol, and brush the sur- 

 faces with a camel-liaii' pencil ; next, place it in absolute alcohol for 

 a few minutes, from thence into oil of cloves till quite clear, then 

 into clean oil of cloves for ten or fifteen minutes, or until ready for 

 mounting ; for which use balsam in benzole as for sections. 



Preparations stained in the blue may be left in oil of cloves for a 

 week or more without injury. When mounting, in order to facilitate 

 drying, adopt the plan given for sections. 



Magenta dye may be used in the study of the vascular system of 

 leaves, as here its fugitive character is of great value, for by its use 

 vessels may be stained, and the parenchyma left colourless. For in- 

 stance take a young leaf or frond which has been prepared for staining, 

 and let it be in the magenta for an hour or two, transfer it to alcohol, 

 and the colour is very quickly discharged, but, upon examination, 

 it will be found that the spiral and other vessels are beautifully 

 stained. 



Again, it may be desirable to stain the immature fructification of 

 a fern, so as to leave all else colourless. This may readily be done 

 by placing the preparation in magenta for about ten minutes, then 

 washing in alcohol till colour is removed from the lamina, it will then 

 be found that the sporangia are delicately stained, and the spores of 

 a deeper tint. 



This method is also applicable to ovaries, the readiness with which 

 this colour is given up by the tissues enabling us to use it so as to 

 leave the ovules stained, while the wall of the ovary is colourless. 



These are only given as examples ; other instances will suggest 

 themselves where this colour and method will be of value. 



Dr. Beatty, in his paper, advises the use of mature leaves, not the 

 very young, nor the old. Now it will be at once apparent, that a 

 large amount of interest attaches to the development of tissues and 

 organs, and that this can only be studied while the leaf or organ is 

 in a very young state. A considerable difficulty was at first expe- 

 rienced in fixing the colour in very young tissue, the ordinary method 

 of washing, &c, discharging the colour almost immediately. This 



