PROTOPLASM AND NUCLEUS 27 



This reaction may with advantage be performed in the bulk, 

 by cutting some shavings of cork, and boiling them for some 

 minutes in Schulze's macerating fluid : they will be seen to lose 

 shape, and coalesce into a viscid mass : this is soluble in warm 

 alcohol, benzol, &c. 



II. Protoplasm and Nucleus. 



The protoplasm of the cell, and the nucleus, may be observed 

 in the living condition as described in the preceding chapter ; 

 but in order to recognize the more minute details, and in order 

 to make permanent preparations of these bodies, more com- 

 plicated methods of treatment are necessary. 



The protoplasm and nucleus must be first fixed and hardened 

 (see above, p. 4) : the best hardening agent is absolute alcohol ; 

 if picric acid be used it must be very completely washed out 

 from the tissues before staining. 



Harden the young flowering stem of a common Hyacinth, 

 not more than three or four inches in length, in alcohol : cut 

 longitudinal sections of the basal portion of it, and stain with 

 Kleinenberg's haematoxylin (see Appendix A) till the sections 

 are deeply coloured, then wash thoroughly with absolute 

 alcohol in a watch-glass : transfer them (drying off all super- 

 fluous alcohol with blotting-paper) to oil of cloves, or tur- 

 pentine and creosote (see Appendix A), in which they should 

 be left for some minutes, so that the fluid may thoroughly 

 permeate them : then mount in Canada balsam dissolved in 

 benzol. 



Examine sections thus treated under a high power, and 

 observe the chief bulk of the tissue to consist of square or 

 oblong cells of considerable size : the following parts are to be 

 recognized 



1. The cell- wall, which is uniformly thin and is stained. 



2. The protoplasmic lining or primordial utricle, which is 

 also stained. 



3. A large central vacuole, which is not stained, and is 

 usually traversed by fine bridles of slightly stained granular 

 protoplasm : these suspend in a central position 



4. The deeply stained nucleus : it may be observed in many 

 cases that the nucleus does not occupy a central position, but 



