234 1IOW TO WORK 



work on Anatomy and Physiology woodcuts from photographs of the 

 microscopic objects, and Ur. Herupath, of Bristol, adopted a similar 

 method for his paper on the Spicules and Plates of Synapta, pub- 

 lished in the Quarterly Journal Mic. Science. 



Photography has been used by Dr. Maddox.to illustrate a paper 

 presented to the Royal Society, June, 1867 ; the photographs being 

 made from an aquatic Larva whilst living. 



Many anatomical specimens, however, cannot be copied by 

 photography, especially if they be very thick. The yellow colour 

 of the tissue in most instances precludes the possibility of making a 

 photograph of it, as the transmission of the light is so much interfered 

 with; and this is an especial objection in the case of injections 

 viewed as transparent objects, for the tissue intervening between the 

 vessels is often so yellow that these intervals in the photograph 

 become as dark as the vessels themselves. My friend Dr. Julius 

 Pollock has nevertheless succeeded in obtaining for me some very 

 tolerable copies of injections of the distribution of the ducts in the 

 liver. By practice, doubtless, many improvements in the process of 

 taking photographs of such microscopic objects would be effected. 



When only few copies of a work are required, the researches may 

 be very cheaply illustrated by taking photographs of drawings. A 

 large drawing of the object must first be made in the manner 

 described in p. 27. From this a negative reduced to the proper 

 size is taken, from which any number of copies may be obtained. 

 In this manner I have illustrated my memoir on the anatomy of the 

 liver, with upwards of sixty illustrations (The Anatomy of the 

 Liver, 1856). The results were not so satisfactory as they might 

 have been, but as all these prints were prepared at home with very 

 limited appliances, very good prints could not be looked for. When 

 many copies of a work are likely to be required, this mode of illus- 

 tration is not applicable, as the original cost of engraving would soon 

 be covered ; but when only a few copies of a great number of draw- 

 ings are wanted, this plan possesses decided advantages. 



From the great success of Mr. Walter Woodbury's and Mr. Swan's 

 process of carbon printing, and the facility with which large numbers of 

 prints can be produced, there seems every chance that the cost of illus- 

 tration will be materially lessened, and greater permanence secured. 



324. illumination. Different modes of illumination have been 

 employed. Mr. Delves has used, sunlight. Mr. Shadbolt, in 1852, 

 tried some experiments with artificial light, and succeeded satis- 

 factorily with a small camphine lamp. Mr. G. Busk employed 

 gaslight from an argand burner in 1854; and in N.ovember of the 

 same year Mr. Wenharn states that,, although with the use of camphine 



