104 VEGETABLE CELLS. 



7. Mucilage-globules, of equal size with the preceding, 

 partly homogeneous, partly very slightly granular, with a 

 cavity and a nucleolus contained in it, 



8. Like 7 ; but with several cavities, and as many 

 nucleoli. 



9. Like 7, with one or more solid nucleoli, and no 

 cavity. 



10. Larger homogeneous or slightly granular mucilage 

 globules, of clearer, more transparent substance, with or 

 without cavities, with or without nucleoli. 



11. Clear vesicles, of the size of 10, with or without 

 nucleoli. 



12. Mucilage-globules, like 10, or utricles, like 11, 

 surrounded by a thin layer of homogeneous mucilage, 

 which is usually thinner on one side than on the opposite. 



13. Like 12 ; the mucilaginous layer has considerably 

 increased in size on one side, become somewhat granular, 

 and displays a very indistinct membrane on its periphery 



14. Like 1, namely, distinctly perfect cells, with per- 

 fect nuclei and distinct nucleoli. 



These are the principal and most frequent forms of 

 organization that are found in the fluid of the embryo- 

 sac, and which are of importance in the processes which 

 go on. A quantity of intermediate stages between the 

 various forms here enumerated are rather calculated to 

 confuse the vision and judgment than to make a pro- 

 cess clear through a complete history of the gradual de- 

 velopment. Observation of these matters has to strive 

 against two obstacles, which appear to me almost insur- 

 mountable : one depending on the fact that partial changes 

 ensue very rapidly in the solid portions of the contents, 

 especially when water is applied the other, that the dif- 

 ferent stages of development are all mixed together, and 

 thus, without the help of extraneous characters, are ne- 

 cessarily judged of merely by their own individual aspect. 



Schleiden, it is well known, has interpreted the pheno- 

 mena in this way : that a number of mucilage-granules 

 become confluent to form nucleoli ; that the nucleoli 





