THE REPRODUCTION OF FISHES IN PAPER PULPS 265 



When a sufficient quantity has been made, oil the mould 

 thinly and press the pulp firmly into it, kneading the pulp well 

 into every depression, but as thinly as possible, for, wherever this 

 precaution is neglected and it lies as a thick mass, so surely 

 will a loss of definition be subsequently observed, the increased 

 thickness not allowing sufficient pressure of the fingers and 

 thumbs being brought to bear to force the pulp into all the 

 patterns and interstices of the mould. 



When the mould is thinly covered with the pulp, lay 

 upon it some pieces, not too large, of muslin, well pasted on 

 both sides, to form one layer at first, this being superior to 

 paper, which has sometimes been the chief cause of the trouble- 

 some thickening of the folds in the deeper cavities, and a 

 consequent loss of definition ; this also has been due to the 

 tissue or other paper with which the pulp was formerly backed 

 getting out of place, or working up as a thick mass. About 

 three layers of muslin will give sufficient strength as a backing, 

 but in fins and small specimens one is sufficient. It is neces- 

 sary, some hours after finishing, to examine for " blisters " in the 

 muslin, and these parts must be re-pasted and rubbed down with 

 the fingers. On an irregular surface the muslin must be put down 

 in small pieces, cut to shapes best adapted for being laid down 

 without wrinkling ; otherwise they will lift or contract over the 

 depressions when drying. The muslin must overlap the pulp 

 at least half an inch all round to prevent curling. When 

 relieving the model from the mould, pass a thin knife under 

 this edge of muslin, and gradually relieve everywhere. As 

 before stated, these models should be dried slowly, at least a 

 week being allowed. Should the weather be damp and it be 

 found necessary to expose them to a fire, they should be placed 

 at a considerable distance from it, or they will be twisted out 

 of shape. 



By means of the backing of muslin, the model, when dry, 



