1887.] MICROSCOPICAL JOURNAL. 151 
erased readily, and because shading can be done so much more expeditiously, 
and by the unskilful with so much better effect. A judicious use of both the 
pen and pencil will secure results which improve upon the best work of either 
alone. Outlines can be brought out with decision, while broad tints are 
put in with a pencil with fine effect. Where pencil is employed, and enough 
of the graphite thrown on the paper to endanger blurring should the draw- 
ing be rubbed, it should be ‘ fixed’ or varnished by a coat of white shellac 
dissolved in alcohol, sprayed on with an atomizer. 
In making the drawing the camera obscura should be freely used both to 
obtain an accurate outline and to fill in as many of the details as possible. 
In choosing a camera one should be selected which can be used with the tube 
vertical, as it is often desirable to keep the stage horizontal especially in 
studying living animals. Either the Zeiss camera or the Abbe camera are 
used in this manner and are the most universally convenient, for they may 
be at once applied without change of the position of the instrument. If 
a camera is used which requires the tube to be horizontal, the camera 
should be a compound or erecting prism which furnishes an image on the 
paper in the same position as the one on the stage. The reason for this 
becomes at once apparent on finishing, free-hand, the drawing begun with 
the camera. In the absence of a camera a very good device for obtaining 
an accurate copy of the object in the field, is to draw on the paper a cir- 
cle which is nearly or quite equal to the field of view and rule it with ink 
quadrants, and then draw on the real quadrants the contents of imaginary 
corresponding quadrants of the field. By training the left eye to the micro- 
scope, and the right eye to the paper, the student can, with practise, obtain 
great facility in this mode of drawing, using, of course, one eye at a time. 
He can improve on it by adding other lines to the first two at his own dis- 
cretion. While the camera is on and the position of the instrument un- 
changed, a stage micrometer should replace the slide and a drawing of the 
scale to accompany the picture should be made. 
In the first attempt to copy on paper what is before the eye in the micres- 
cope there is a vast confusion and disappointment. Apparently the task is 
beyond human powers, even with the simplest possible object, as a diatom, 
or hydroid cuticle, or thread-cell, and much greater with a section of animal 
tissue. And this confusion and despair will continue indefinitely unless the 
draughtsman set out to overcome it, and so long as it lasts will prevent suc- 
cess at histological drawing ; and we may go further and say at any natural 
history drawing. Without entering into any of the disputes on standards of 
excellence from the art standpoint, we may say that there is only one first cri- 
terion of excellence in scientific drawing, and that is clearness. The draw- 
ing must represent clearly and unmistakably the structure of the object. Now, 
it will be seen that it is only after such a study of the object as we have out- 
lined as necessary—a study which reveals the plan of structure-—that the stu- 
dent can have a sufficiently clear knowledge of that plan of structure to make 
an intelligible drawing from his object. |. When he has such a knowledge it 
is not very difficult to make a drawing which shall be a visible description, 
so to speak, of the facts which would be embodied in a verbal description, 
and without such a knowledge a good drawing is impossible except from the 
simplest objects. Histological drawing, more than any other, requires the 
exercise of judgment and “sagacity. I am aware that many instructors in 
this art tell the pupil to draw what he sees, but they should add to this that 
he must see with the eye of judgment as well as of mere sensation. Fur- 
thermore, there must be care exercised in selecting a view which best shows 
the ‘ points,’ if the pupil is to draw only what he sees. The precept should 
be to select the best view, draw as much of the detail as skill permits, but 
