314 SUMMARY OF CURRENT RESEARCHES RELATING TO 



object itself rather than to a representation of it. A boy who has 

 seen an elephant or a monkey in the Zoological Gardens has a great 

 advantage over his companion who has only seen pictures of these 

 animals. In the same way the anatomical dissection of the human 

 body itself must be thoroughly understood by the medical student, 

 and cannot be replaced by the observation of any artificial model, 

 however skilfully constructed. The same principle applies to botany. 

 Pictorial representations of plants and their parts can in no way 

 replace the necessity for a personal examination by means of the 

 Microscope and the dissecting knife. 



One of two methods are usually employed in using the Microscopes, 

 i. e. they arc either passed from hand to hand, or are fixed in the 

 lecture room. The first method has the advantage that the explana- 

 tion is immediately connected with the observation of the object, but 

 it is likewise attended with the great disadvantage, that the larger 

 the audience, the more likely is the position of the instrument to be 

 disturbed, and the object displaced. Besides, while the student is 

 looking at the Microscope, the lecturer has, perhaps, proceeded to 

 another object. 



The second method is intended to remove the inconvenience of the 

 former. Several Microscopes are set uj), and certain hours fixed for 

 demonstration, and thus the disturbance of the object is avoided. 

 A more serious inconvenience arises however from the fact that it is 

 impossible for the teacher to give an oral explanation, because each 

 student has a different object before him. 



Whilst the actual microscopic image is indispensable, it is never- 

 theless not sufficient by itself, and recourse must often be had during 

 the lecture to diagrams ; for this purpose the Sciopticon has been found 

 exceedingly useful. Its advantage lies in its cheapness, and in the 

 very strong light thrown upon the object, consequent upon the ar- 

 rangement of the lamp and the ventilation. Three kinds of objects 

 can be used with it. First, for a small audience, the microscopical 

 preparation itself ; secondly, photographs from the preparations ; and, 

 thirdly, photographs from diagrams. Great care in making the photo- 

 graphs of specimens is necessary. For example, sections of wood or 

 bark must be perfectly thin and even, that the photograph may be 

 clear and not perplexing to the beginner by too great a number of 

 unessential parts. Photographs from diagrams have the great ad- 

 vantage of giving the whole development of an organism or an organ 

 in the same diagram, and differently magnified, according to the 

 requirements of each object. 



Every object is not, however, suitable for this kind of demonstra- 

 tion ; for example, the photograph of a diatom is to be preferred to 

 one made from a drawing of it. 



" All objections which teachers formerly made to the Sciopticon 

 have disappeared, after the experience of many years. My audience 

 comprises 60 students, and those at the end of the room can see the 

 images almost as clearly as those in front. Some teachers have 

 expressed the fear that young students would take advantage of the 

 darkness to play mischievous tricks, but it will be found, on the 



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