86 ALDRIDGE ON POLLEN. 



them. As soon as I am able to walk and can find an oppor- 

 tunity, I will send you specimens of some of the plants I 

 have met with since I sent you the things by the Shepherd. 

 Of the Natural Order Proteacece, I have now collected about 

 two hundred and forty species." 



J. D. 



IV. — On the Structure and Functions of the Pollen. By 

 John Aldridge, M.D., Lecturer on Natural History to 

 the School of Surgery and Medicine, Digges Street, Dub- 

 lin ; Member of the Dublin Natural History Society, &c. 



In the September Number of the Journal of Botafiy, I de- 

 scribed some observations which 1 had made on the process 

 of impregnation in plants. A more complete account of 

 these observations was made to the British Association at its 

 subsequent meeting; and on the same occasion an Atlas was 

 exhibited, which presented drawings of the appearances ex- 

 hibited by the Pollen of the greater number of Natural 

 Families, in the dry state, when moistened with water, and 

 when burst through the contact of acids. I stated, on 

 both these occasions, the results of my investigations to be,' — 

 first, that the stigma is invariably acid at some period of its 

 growth; secondly, that it is in consequence of this acidity, 

 that the pollen bursts ; thirdly, that by the same means, the 

 fluid contents of the pollen become coagulated, enveloping 

 the fovijla, and assuming, according to the method of dehis- 

 cence, different, and very remarkable forms. 



Unable to attend personally the meeting of the British 

 Association, I felt happy in the assurances of my friends, 

 that the many eminent men present, appeared prepared to 

 admit the results to which I had been conducted. It was 

 asserted, however, that my views were not original, but were 

 already contained in the works of Mohl and Fritzche. 



As the determination of the truth is of much greater im- 

 portance than any thing connected with individual reputation, 



