82 micJroscopic objects. 



dispersed to a distance. The foreig-n species named in 

 the Catalogue, from the author's cabinet, offer great 

 variety in their structure, and are among the most inter- 

 esting for the microscopist as opaque objects. 



The development of Ferns may be observed by 

 placing the spores in moistened flannel and keeping it at 

 a warm temperature. At first a single cellule is pro- 

 duced, then a second, and so on. After this the first 

 cellule divides into two, and then the others, by which a 

 lateral increase takes place. 



Magnifying power for the Ferns 30 to 80 diameters. 

 For the spores 150 to 300 diameters. 



Fossil Vegetables. — ^The perfection to which the art of 

 cutting fossil woods into thin sections not thicker than 

 banknote-paper, and thus rendernig them pervious to hght, 

 has enabled the botanist to examine by the microscope 

 all the minutiae of their structure. So perfect is their 

 organisation preserved in the fossil state, that in some 

 cases the true form of the glandular discs on woody fibre 

 has been demonstrated when it could not be done in the 

 recent state. Although thin sections of fossil woods are 

 necessarily more costly than those of recent ones, yet no 

 collection of microscopic objects should be without 

 examples. Fossil woods may also be viewed as opaque 

 objects, in which case it is merely necessary to smooth 

 and pohsh the surface. 



Mr. Pritchard, who some years ago introduced the 

 cutting of thin sections of fossils, prepares on each slide, 

 transverse and longitudinal sections of the same speci- 



