68 Mr. Howard's Account of a MlcrofcopicalJnv.Jilgatmt 



If a pillil be feparateci from the expanded flower with grains of 

 pollca adhering to it, the latter will be found already expanded to 

 a fpheroid. Cover the whole with a drop of fpirit on the glufs, the 

 piftil is not affected in any way, but fome of the grains quit it and 

 revolve on their axes. When thefe are exhaufled, the addition of 

 more fpirit excites others: after a few minutes, fome of thofe firft 

 excited begin to.put out a fmall thread, which gradually elongating,, 

 the grain diminilhes in proportion, until it is entirely drawn out 

 into a vermicular fibre,, which again is prefently diflipatcd into par- 

 ticles too minute to be feen in the now opake medium. The liquor 

 from the tube of the piftil, and a folution of fugar in water, were 

 alfo found to produce this evolution in very mature grains 

 from the anther. It alfo fometimes takes place in the twinkling of 

 an eye, fo as to be fcarcely traced in fome few grains out of a 

 number put into fpirit at once. Thofe which have been fome time 

 in contact with the piilil are always moft flnggiih in their evo- 

 lution. 



5. Car ex acuta. 



Anthers oblong, crumbling. Pollen angular, opake, with apparent 

 perforations. It dilates in fpirit and remains flationary, but ejects 

 numerous minute particles in rapid fuccelfion from its furfacc* 

 When it has become tranfparent it appears as if filled with feeds. 



The preceding may ferve for examples of thefe ph'cEnomena ; but 

 there was not one among the various fpecies I examined, which did 

 not exhibit them in a greater or lefs degree. Yet various other parts 

 of the flower, immerfed in fpirit under the microfcope, did not be- 

 tray the fmallefb veflige of them. 



The proper fpirit for this purpofe feem^s to be a mixture of one 

 part pure fpirit of wine with two of water. A flronger fpirit, or 

 even fpirit of wine alone, may fometimes be required when we ope- 

 rate upon a pollen which has, by any means, become previoufly 



6 ' faturated 



