Human Physiology. 



Many flowers are provided with organs which secrete honey; 

 this honey is stored in deep vases, very deep sometimes, as in 

 the Columbine. Bees and other insects, and even some birds, as 

 the humming bird, attracted by the honey, and seeking it in its 

 deep cells, unconsciously aid in the process of generation. The 

 pollen adheres to their bodies or wings, and is brought in 

 contact with the stigma of the same flower, or others of the 

 same species, to which it is made to adhere by a viscid 

 secretion. All flowers do not contain both male and female 

 organs of generation. They may be on different parts of the 

 same plant, as in the maize, or Indian corn, where the pollen 

 is produced on the very top of the tall stalk, sometimes twenty 

 feet high, while the long silky pistils grow from the cob which 

 holds the germs in rows about the middle of the stalk. Some- 

 times the male and female flowers are on 

 different trees or plants, and their propagation 

 is entirely dependent upon insects or favour- 

 ing breezes. 



When the pollen cell, containing the 

 fecundating element falls upon the stigma of 

 a flower, adhering to its viscid secretion, a 

 very beautiful vital process commences. The 

 inner membrane of the pollen extends itself 

 into a tube which penetrates into the style, 

 which is sometimes two or three inches in 

 length, until it reaches the germ in the ovary, 

 where it penetrates the germ, or meets a 

 corresponding tube thrown out by it. The 

 two elements unite, the germ is fertilised 

 and grows into a seed, the egg of the plant, 

 in which is formed, and from which is de- SECTION OF PISTIL, 

 veloped the new plant which is to continue with Pollen Grains, 

 the species. The living germ of the plant is sending Tubes down 

 very small, quite microscopic in its dimen- to the Ovar y- 



Fig. 58- 



