/O Mr. Howard's Account of a Microfcopical Invejllgathn 



tlon?, that the pollen of vegetables is in all cafes fimilarly aftcd 

 upon by water and by fpirit of wine, it will follow, — 



1. That each grain of pollen in the anther is an organic body, 

 varioufly conftrufled in various fpecies, and containing 



a Vcffels or pores capable of imbibing water, of diftending thereby 

 and con trading again when It quits them ; in which particulars they 

 rcfemble fpongc, &c. 



b A parenchyma, confining of fome fubftance (of greater fpecific 

 gravity than water, and infoluble therein), which is emitted with a 

 greater or Icfs degree of force when the ftimulus of alcohol is applied 

 to the abforbent veffels. This fubftance is either in part foluble in 

 alcohol, or the grains contain 



c An effentiai oil or refin, to which they owe their colour and 

 odour. 



2. That there exifls in the grains of pollen, in a very eminent 

 degree, that property of vegetables called irritability, which they 

 are capable of retaining for a certain time after fcparation from the 

 anther. 



3. That alcohol is the proper ftimulus by which this irritability 

 may be excited, and the texture of the pollen in fome manner deve- 

 loped in confequence thereof. I prefer this method of accounting 

 for the appearances that take place when the pollen is immerfed in 

 fpirit to another that might be fuppofed on chemical principles, 

 being alTared, that any one who has once iiifpe£tcd the procefs will 

 be fatisfied that fomething more than mere folution or chemical 

 decompofition takes place therein, and that the vital principle of 

 the pollen is the chief agent. 



The liquor from the tube of the piftil and the folution of fugar 

 were, indeed, found to bring on the evolution of the pollen oiCa£lui 

 flagel,]Xid. flower manner than fpirit; but when we confider how 



fpeedily 



