176 METHODS OP MICROSCOPICAL RESEARCH. 



never touches perfect precision ; on the other hand, 

 a draughtsman may arrange a minute and just 

 perspective of parts, absent in a photograph, antici- 

 pating the presence of relative parts, and having 

 at command the fine adjustment, he can feel his 

 way, conscious that at the slightest touch a fresh 

 point, perhaps an important revelation, flashes into 

 sight, supplying a link to the better understanding 

 of the whole. A drawing, produced under thought- 

 ful guidance, conveys to an appreciative observer 

 an attraction totally absent from a photograph; 

 the latter may possess the important and essential 

 element of proportion and freedom from exaggera- 

 tion, but exactitude is never absent from a drawing 

 disclosing understanding, and conscientious treat- 

 ment. 



There may seem little or no analogy between 

 landscape and microscopical painting, but the same 

 principles are involved points of sight, effective 

 light, general entourage possibly a " preparation," 

 dealing with unusual and unexpected complications 

 of line, embracing physiological difficulties, requir- 

 ing delicate conditions of luminosity, demands a 

 deeper judgment, for it is often necessary to pre- 

 pare the mind by careful and prolonged study, 

 before the paper is touched ; especially in consider- 

 ing and anticipating difficulties of representation, 

 and how they may be overcome delicate structures, 

 under the most careful illumination, often appear as 

 streaks of LIGHT, when a slight touch of the con- 

 denser may reveal distinct lines. These are points 

 to be studied ; in fact, the subject should be " gone 

 over " and arranged in all particulars, so that it may 

 not outstrip the power of the pencil. All materials 



