When finished, the edges of the various parts may appear woolly owing to the rubbing of the lead; this may be cured by cleaning up the edges with a trimmed piece of India rubber, but in so doing there is always a risk of rubbing out part of the shading, especially if the outline be at all intricate. If preferred, all the shaded parts may be fixed by painting them over with a suitable solution, gelatine for instance, paying particular attention in following the correct outline. When dry, the application of soft india-rubber will soon clean up the blurred edges. If charcoal be used the same procedure may be followed. Charcoal and pencil drawings should be fixed, in order to prevent rubbing, before sending to the block makers. A suitable fixative may be purchased or one may be made by dissolving white resin in alcohol and applying it to the paper by means of a scent spray or an atomizer. A very good fixative may be made by dissolving a little gelatine in hot water and applying it whilst hot by means of a broad, flat camel hair brush, or ordinary milk may be used in a similar way. After the fixative has been put on, the drawing should be pinned up by one corner--unless, of course, it was pinned up before the fixative was employed, which is the best way when the fixative is an alcoholic solution--and allowed to dry; it may then be placed under pressure in order to flatten it, for fixed drawings generally shew a tendency to curl, especially when the preparation used for fixing has only been applied to one surface of the paper. In making drawings for reproduction by means of the half-tone process, there are a few general points to which attention should be paid. It should be remembered that there is not infrequently a tendency towards flatness in the reproduction; it is therefore important that the originals should be "plucky," and, on the whole, it is better to exaggerate with regard to high light and shade, especially if there is much modelling or perspective. Finally, with regard to lighting, it is better for the majority in drawing their objects--solid objects in relief are referred to--to use a more or less lateral illumination and to represent only the high lights, shades and shadows referable to this main direction of illumination. A high relief will thus be obtained, and the effect will prove more satisfactory than if minor sources of illumination are unsuccessfully dealt with. This is especially important in drawing complicated structures such as models of vascular tissues, embryos, etc. In cases where many such figures are to occur on one page, it is highly desirable that the lighting of each should be from the same direction.