THE MICROSCOPE. 67 



botany and zoology the conduct of instruction in certain courses, 

 which are generally given to small classes, must rely on the use of 

 the microscope in immediate connection with the instruction. Such 

 are courses in the fructification of alga, in the forms and structures 

 of diatoms, in the forms and structures of infusoria, and in the 

 development of the embryo. Entirely similar are the requirements 

 in paheontological courses, involving the study of the minute 

 structures of the shells of fossil brachiopods, or of the coral skele- 

 tons of polyps. The same must be said in courses requiring the 

 study of the optical characters of minerals. Moreover all the 

 advanced courses in the 'subjects consist of researches through a 

 wide range of specimens belonging to a given class, and which must 

 be obtained from the museum collections. Finally, the methods of 

 preparing many of these specimens are quite unlike those employed 

 in the simpler and more usual line of research, so that some special 

 appliances have to be provided which it would be a useless expendi- 

 ture to provide for ordinary microscopical work. 



"The following are the branches of science in which microscopic- 

 al work is at present carried on in the University: 



Human Histology. 



Comparative Histology. 



Vegetable Histology. 



Botanical Research. 



Zoological Research. 



Palaeontological Research. 



Pathological Anatomy. 



Psychological and Analytical Chemistry. 



'• As a rule, every student entering upon the use of the micro- 

 scope in any one of these branches is under the necessity of acquir- 

 ing in the university the skill requisite for successful manipulation. 

 Manifestly, therefore, some advantage would be gained by sending 

 students first to a central school of microscopic manipulation. Here 

 they might be at first restricted to the use of cheap instruments, 

 and thus, perhaps, some costly accidents would be avoided. 



" But students learning to use the microscope must employ some 

 suitable objects for examination. These are preferably the ordinary 

 tissues of plants and animals. The study of the microscope involves, 

 therefore, the study of general histology. By the time adequate 

 expertness has been acquired in the use of the instrument and its 

 accessories, the student has made such progress in either vegetable 



