2S4: ON THE STUDY OF BIOLOGY x 



able he sliould know it; but he will have enough 

 real knowledge to enable him to understand what 

 he reads, to have genuine images in his mind of 

 those structures which become so variously modi- 

 fied in all the forms of insects he has not seen. 

 In fact, there are such things as types of form 

 among animals and vegetables, and for the pur- 

 pose of getting a definite knowledge of what con- 

 stitutes the leading modifications of animal and 

 plant life, it is not needful to examine more than 

 a comparatively small number of animals and 

 plants. 



Let me tell you what we do in the biological 

 lal)oratory which is lodged in a building adjacent to 

 this. There 1 lecture to a class of students daily 

 for about four-and-a-half months, and my class 

 have, of course, their text-books; but the essential 

 part of the whole teaching, and that which I re- 

 gard as really the most important part of it, is a 

 laboratory for practical work, which is simply a 

 room with all the api)liances needed for ordinary 

 dissection. We have tables properly arranged in 

 regard to light, microscopes, and dissecting instru- 

 ments, and we work through the structure of a 

 certain number of animals and plants. As, for 

 example, among the plants, we take a yeast plant, 

 a Protococcus, a common mould, a Chara, a fern, 

 and some flowering plant; among animals we ex- 

 amine such things as an Amoeba, a Yorticella, and 

 a fresh-water polype. We dissect a star-fish, au 



