LABORATORY STUDIES AND DEMONSTRATIONS. 213 



If time presses, tlie detailed study of iiiicroscopieal sections 

 may be omitted, but a series of prepared sections shcnild be kept 

 on liand and a demonstration given. 



The embryological development is too difficult to study, but 

 very instructive demonstrations may be given l>y those who have 

 had some experience. In the neighborhood of Philadelphia egg- 

 capsules may be found in great numbers in old manure-heajis, 

 in May and June. One end of the capsule should be slicc(| olf 

 with a very sharp scalpel and the contents drawn out, under 

 water, with a large-mouthed pipette. The mass may then be 

 mounted in water under a supported cover-glass and studied 

 with the microscope. The embryos may be preser\ed in 

 Perenyi's fluid, and either studied whole in the preserving fluid 

 or hardened in alcohol and cut into series of sections. 



Chapters IX to XI. (The Common Brake.) 



Except when the ground is frozen Pteris may be dug up and 

 brouii:ht into the laboratorv in a fresh state. Fronds mav be 

 cut and dried in midsummer and considerably freshened (by a 

 moment's immersion in warm water) when needed to be used (in 

 the oj^ening exercise) to illustrate the aerial portion of the plant. 

 Rhizomes may be obtained at convenience and kept in weak 

 alcohol (50^). 



The Morphology of the Body. To illustrate this, one whole 

 and entire plant should, if possible, be at hand for examination. 

 The aerial and the underground portions may then be sketched 

 in their normal relations. Branches, roots, and old leaf-.<talks 

 should be pointed out, identified, and sketched. 



The Anatomy of the Rhizome should first be made out \\\\\\ 

 the naked eye. The lateral ridges will be detected by the class, 

 which should be asked to draw the cross-section as seen M'ith 

 the naked eye. For this preliminary work each student should 

 have a piece of rhizome two or three inches in length. (Care 

 should afterwards be taken that the drawing has been correctly 

 placed dorsoventrally.) A rough dissection with jack-knife or 

 large scalpel may next follow, with inferences as to the characters 

 of the several tissues found (as fibrous, pidpy, woody, etc.). 



The Microscojy'iG Anatomy of the Bh home is interesting, and, 



