4> PROFESSOR RUTHERFORD. 



scope. If the microscope be one that is thoroughly satisfactory, 

 such as Hartnack's, the labour of tuition is light ; but if it 

 is one of those clums)'^ machines so commonly met with in 

 this country the labour is fearful. 



The microscope which, in my opinion, is by far the 

 best, both for the student and any one who wants really 

 to work, is that made by Hartnack. It is so easy to work 

 with it. The stage is just high enough to permit of the 

 hand moving the slide without the arm being raised from 

 the table. That expensive and time-wasting apparatus, the 

 moveable stage, is absent. I generally recommend this 

 apparatus for persons who cannot learn how to properly 

 regulate the movements of their fingers. The coarse adjust- 

 ment is effected by sliding the tube up or down without 

 the use of a rack and pinion — another expensive and useless 

 addition. Some persons say, that without the rack and 

 pinion the student will bring the lens doAvn on the cover- 

 glass, and break the preparation or, it may be, the lens. 

 After having given twenty-six courses of Histology, and 

 after having taught some five hundred students, I am 

 glad to say that I never had a lens injured, and I have 

 only had two covering glasses of preparations broken in this 

 way. The student only requires to be carefully instructed 

 on this point when he begins to work Avith the m.icroscope. 

 Hartnack's lenses, too, are so excellent, that the student 

 can easily see things clearly, and not in a mist, as is the case 

 with most English cheap lenses, and with the majority of 

 Gundlach's l-8th, which find their way to this country. In 

 the matter of microscopes tastes vary much, of course; but, 

 for my part, I can say, that while I have found it satisfactory 

 and comparatively easy to teach a class with Hartnack's 

 microscope, I have found it terrible labour to do so with the 

 ordinary educational microscope of these realms, Avith its 

 great long tube, always needing the pillar to be bent, or 

 compelling one to stand in order to look through it when it 

 is vertical, its stage far too high, &c. I therefore think, 

 that the first great essential for the successful tuition of 

 Histology is to place the student in possession of a thoroughly 

 good microscope on Hartnack's model. Such microscopes 

 are made by Mr. Crouch, but his lenses, though superior to 

 the general run of Gundlach's l-8th's, are not quite equal to 

 Hartnack's. 



Some teachers give the student a programme of what he 

 is to do at each lesson, and let him proceed to work upon it 

 independent of the other students. The argument urged in 

 favour of this plan is, that the good are not held back by the 



