INTRODUCTION TO CRYPTOGAMIC BOTANY. 25 



dying successfully. Questions often arise as to the point whether 

 cellular structure can originate without the presence of aprevious 

 mother cell. It is a question, for instance, whether cells are 

 ever formed in Phsenogams from mere organisable sap, as 

 presumed by Mirbel in his paper on the Date Palm ;* or again, 

 whether, in what is called organisable lymph in the animal 

 world, cells can originate freely without puUulation from 

 neighbouring tissue with which the lymph is in contact. 

 In the blood, once more, are blood globules, or in imhealthy 

 conditions pus globules, ever formed simply from the consti- 

 tuents of the blood itself, without the concurrence of previously 

 formed organisms ? Now in those fungi in which, as in Sphoeria 

 and Peziza, the reproductive bodies are generated by the 

 endochrome of the fructifying cells, the Cryptogamist has the 

 power of watching the development of the spores from the 

 very moment when the endochrome commences to be organised, 

 and he can with confidence assert that they are not the 

 creatures of previously-existing cells, but the produce of the 

 endochrome itself He will be able to compare with this 

 what takes place in the embryo sac of Phsenogams, and will 

 be better prepared to appreciate all the arguments which bear 

 upon the Schleidenian Theory of the formation of the embryo. 

 Both the formation of the albumen and of the embryo itself 

 will then be studied with greater zest, and he will certainly, after 

 watching the origia of spores within an ascus, be able to judge 

 better of what takes place or does not take place within the 

 pollen tube. It is true that many of the points I have 



Fig. 10. 



Glceocapsa rupestris, Kiitz, magnified, from specimens commuuicated 

 by M. Br^bisson, from Falaise. The simple spore has first given rise 

 to two new spores, and then to four. 



* Ann. d. Sc. Nat. Ser. 2 vol. xi. p. 321. 



