518 HISTOLOGY 



sections and of the side view identical; the measurements may be en- 

 larged or reduced as they are transferred for plotting, by means of the 

 draughtsman's proportional dividers, an indispensable instrument for 

 this method of reconstruction. The corrections for unequal shrinkage 

 of the sections in paraffin, and other details, can best be explained in the 

 laboratory with the drawings at hand. 



In addition to making side views, this method may be used in recon- 

 structing ventral or dorsal views, by plotting outward from the median 

 line. 



DRAWINGS. 



Since anatomy, both gross and microscopic, is a study of forms and 

 relations, that is of things seen, it finds natural expression in drawing; 

 and the volumes of wood-cuts, copper-plates, and lithographs, together with 

 the cheaper process-drawings and half-tones of the present day, form 

 almost as important a part of anatomical literature as the accompanying 

 text. Often there may be shown in a figure at a glance what pages of 

 writing fail to make clear; and it is significant that the great books of 

 Vesalius, which marked a new era in anatomy, were illustrated by Jean 

 de Calcar, a pupil of Titian. Burggraeve believes that Vesalius doubtless 

 supplied preliminary sketches and adds "Almost all the great anato- 

 mists were no less excellent draughtsmen Scarpa and Cuvier furnish 

 us remarkable examples and one can hardly imagine an anatomist who 

 is not deeply sensitive to the beauty and harmony of contours and forms." 

 Selenka (1842-1902) drew the ape embryos, which he collected and de- 

 scribed, with consummate skill, and " always impressed upon his students 

 the great value of a ready pencil." Robert Hooke (1635-1703) was far 

 less successful with his drawings. In the preface to his fully illustrated 

 microscopical observations, he makes the following explanation of the 

 defects of his plates, and in conclusion sets an example which all students 

 should follow. He says 



"What each of the delineated Subjects are, the descriptions annext 

 to each will inform, of which I shall here, only once for all, add, that in 

 divers of them the Gravers have pretty well followed my directions and 

 draughts; and that in making of them, I indeavoured (as far as I was able) 

 first to discover the true appearance, and next to make a plain representa- 

 tion of it." 



To discover the true appearance of each section and to make a plain 

 representation of it, is by far the best method for beginning the study 

 of histology, and conscientious attempts to represent what is seen in- 

 variably lead to deeper and more valuable observations. Thus drawings 

 are unhesitatingly required of all students, and every effort should be 



