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 IWotes. 



A new material for pathological casts is advocated by Dr. C. W. 

 Cathcart in the October number of the Journal of Pathology and 

 Bacteriology. It is obvious that if it is of service for pathological 

 reproductions, its usefulness can be extended to many other sub- 

 jects. In searching for some material for casts, Dr. Cathcart 

 turned his attention to the papier-mache methods. His principal 

 difficulty was to get surface detail, and after trying many papers he 

 found none so satisfactory as the " Robosal" blotting-paper, which 

 is made of wood pulp, and while very strong and tough while dry, 

 is exceedingly absorbent, and when wet becomes very soft and 

 pliable. It is made of various thicknesses and almost any shade 

 of colour, although white is preferable, because it may be coloured 

 afterwards according to the specimen. 



The surface detail on casts made of " Robosal " is quite fine 

 enough for ordinary purposes. Thus, the skin markings on the 

 back of the hand can be brought out distinctly. It is much 

 cheaper than plaster of Paris, and being only a hollow shell of 

 paper weighs in ounces what the other weighs in pounds. It is 

 tough and can be knocked about with impunity. The interior of 

 the moulds., which of course are of plaster of Paris, must be well 

 smeared with vaseline, tallow, or other greasy substance to which 

 paste will not stick. 



The method is described as follows : — " The casts are made of 

 'Robosal' blotting-paper (Messrs. Robinson, Liverpool), about 

 the thickness of ordinary writing-paper, and ordinary flour-paste. 

 After the mould has been prepared as above, a piece of ' Robosal ' 

 is laid on a flat plate and the paste is rubbed into it on both sides 

 till the paper is Hmp and soft. While the softened paper is still 

 lying flat on the plate, scraps are torn from it so as to leave their 

 edges frayed and thin. If necessary, the paper can be torn into 

 thin films, where finer markings are to be cast. Beginning at the 

 margin of the mould on one side, the operator lays on a piece of 

 the torn softened paper, and presses it with his finger or a stiff 

 brush firmly into the irregularities of the mould. Overlapping this 

 he puts on another piece, and another and so on, until the whole 

 of the mould is covered, being careful to avoid wrinkling the soft 

 paper. Over the first layer a second is laid, and sometimes a 

 third. For small casts this will suffice, but for larger casts an 

 additional layer of ' rope,' brown paper, or of muslin, soaked in 

 paste as before, is to be applied in the same way. It is advisable 

 to put on all the desired layers at once, so that in drying they may 

 shrink uniformly. It is also important to let the paper stick to 

 the margin of the mould by leaving them ungreased. This insures 



