Method XVI 93 



paraffin, remove it from the vessel and, still keeping it warm, 

 drain the surplus paraffin from out of the sulci. It may be 

 placed on several thicknesses of filter paper in the thermostat 

 and turned repeatedly for 10-15 minutes, care being taken not 

 to press it while the paraffin is in the melted condition. 



It may then be laid out to cool. When cool, it is a perma- 

 nent preparation and permits of much handling, the paraffin 

 giving it a plastic rather than a brittle consistency. 



If desired, a coat of shellac or oil varnish may now be applied. 

 This will give the preparation a more finished appearance, and 

 also be of some protection to it. 



The chief objection to this method is that it results in a con- 

 siderable shrinkage of the specimen. However, with this excep- 

 tion, the preparation is excellent for purposes of study and 

 demonstration, since the finer relations of the different parts and 

 the general physiognomy of the organ are well preserved. 



The original method of Giacomini' produces somewhat less 

 shrinkage, but results in inconveniences which more than coun- 

 terbalance. Giacomini transferred the brain from the alcohol 

 (4) to a bath of pure glycerine to which had been added about 

 2 per cent, of carbolic acid for aseptic purposes. 



After complete infiltration by the glycerine (8- 10 days) the 

 specimen is removed and set aside for a few days for the glycer- 

 ine to "evaporate" from the surface. Then it may be given a 

 coat of shellac varnish, and the process is complete. 



The specimen prepared in this way is equally capable of being 

 kept in the open air for years, but it is always somewhat sticky 

 and unpleasant to handle, and the glycerine is continually oozing 

 out of it. 



If the brain be fixed and hardened for three or four months 

 in Miiller's fluid (XI, A, p. 69) and then dehydrated in alcohol 

 (4), followed by either glycerine or paraffin (5 and 6), a prepa- 

 ration will be obtained which is less shrunken than those hard- 

 ened in zinc chloride, but the preparation is black instead of 

 the more nearly natural color resulting from the use of zinc 



' Arch, per le Scienze Mediche, 1878. 



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