124 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is gradually increased from 1 to 2^ per cent. The pieces must not 

 be more than 1 to 2 cm. thick, a large proportion of fluid must be used, 

 and it must be frequently changed. In from 15 to 20 days the pieces 

 are put into corrosive sublimate solution j to J per cent, in strength. 

 The reaction requires at least 8 to 10 days, and during this time 

 the liquid must be daily renewed. The pieces gradually change 

 colour and acquire the appearance of fresh brain-substance. They may 

 be allowed to remain even for a longer time in the solution, which 

 serves at the same time to harden them. Sections which are to be 

 kept must be repeatedly washed, else crystals and other deposits appear 

 upon them and alter the appearance under the Microscope. They keep 

 admirably well in glycerine, which is perhaps better for the purpose 

 than Canada balsam and dammar. By this method the ganglion-cells 

 with their processes are acted upon ; their nuclei are often left visible ; 

 the elementary constituents of the walls of the vessels, and especially 

 the smooth muscular fibres (muscle fibre-cells), are also brought out. 

 Golgi rejiorts having had good results from the ajJi^lication of this 

 treatment to the cortex of the cerebrum, negative results in the case 

 of the spinal cord, and but slight success with the cerebellum. The 

 author calls the reaction an apparently black one, inasmuch as the 

 elements on which it has taken effect appear white under surface 

 illumination, and black only by transmitted light. 



Preservation of Anatomical Specimens.* — L. Gerlach recom- 

 mends the glycerine process of Van Vetter, which has been some- 

 what modified, firstly by Stieda and then by Gerlach himself. Stieda's 

 recipe is as follows : — Make a mixture of 6 parts of glycerine, 1 of 

 brown sugar, and ^ part of saltpetre ; Gerlach uses 12 instead of 6 parts 

 of glycerine. TLe preparations are cleaned and laid in this liquid, in 

 which they remain from three to six weeks, according to their size. When 

 taken out they have a dark- brown colour and are quite firm ; they are 

 then hung up in a chamber of the temperature of 12°-14° E. (59° to 

 63.3° Fahr.). In the course of eight to ten days they become soft and 

 flexible, but must be allowed to hang from two to six months longer, 

 to be available for demonstrations. The more glycerine used, the 

 lighter in colour the preparations remain. The method is best applied 

 to prei)arations of articulations, to sense organs (eye, ear), larynx, &c. 

 The formation of a crystalline precipitate, which sometimes appears 

 in the drying, is met by the increase in the proportion of glycerine 

 and a diminution of the saltpetre and sugar. If large objects are to be 

 set up, such as whole extremities with their muscles, or the thorax 

 with the ligaments dissected, pure glycerine is preferable to the cheap 

 crude article, for specimens turn out whiter and less hard in it. 

 Gerlach has used it for temporal bone with tympanum and auditory 

 ossicles, and obtained valuable preparations which may be employed 

 with great success to demonstrate the transmission of waves of sound 

 from the tymjianum to the labyrinth. 



Barff s Preservative for Organic Substances. — A new preserva- 

 tive applicable to all animal and vegetable substances has been 



* SB. phys.-med. Soc. Erlangen, July 28, 1879. Cf. JaLresber. Auat. 

 u. rhysiol., viii. pp. 112-13, and Jahresber. (Virchow and Hirsch) for 1879, p. 2. 



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