1854.] 



71 



of the United States and Mexican Boundary Commission." Referred to 

 Mr. Cassin, Dr. Ruschenberger and Dr. Leidy. 



Dr. Le Conte also presented a paper from Mr. Charles Grirard, on a 

 new species of Salmonidae from the Northeastern part of the United 

 States, which was referred to Dr. Le Conte, Dr. Leidy, and Dr. Hallowell. 



Dr. Brinton desired to draw the attention of the Academy to a new mode which 

 he had recently devised and practised in the preparation of anatomical specimens, 

 several of which he exhibited. 



Anatomical specimens, he said, had hitherto been preserved either in the wet 

 state, or else dried ; both plans were open to objections. 



If animal tissues be immersed in alcohol, or other preservative fluids, their color 

 becomes blanched, their structure condensed, and consequently their size and 

 shape to a certain degree modified ; and at the same time they present incon- 

 veniences for demonstration ; whilst in the dry state, as for example, in the ordin- 

 ary dried preparation of our cabinets, the parts are so shrunken and changed, as 

 to convey but an imperfect idea of their primitive relations. 



As this shrinkage of the tissues, and the decomposition are dependent most 

 probably upon atmospheric influence, Dr. Brinton stated that it had occurred to 

 him some time since, that should he be able so to exclude the air, as to prevent 

 all evaporation from taking place, he would perhaps succeed in preventing, not 

 only the desiccation of the part, but also its decomposition. 



Influenced by this idea, he had commenced a series of experiments, and the suc- 

 cess up to this time accompanying them, had led him to draw the attention of 

 the Academy to the subject. 



His object being to encase hermetically every portion of his specimen, Dr. 

 Brinton remarked that he had selected for his earlier experiments, a solution of 

 gun cotton in ether, the ordinary collodion. This he applied by means of a brush 

 over every portion of the external surface of his preparation. The ether quickly 

 evaporating, a thin film of the cotton was deposited upon and in all the interstices 

 of the tissue. This process was repeated until a layer of sufficient thickness had 

 been obtained; successive coatings of copal and shellac varnishes were then ap- 

 plied, so as to rentier to the preparation a certain degree of firmness and stiffness. 



But it soon became evident to him that collodion was not entirely suited for the 

 generality of objects, especially for those of any considerable bulk. It possesses 

 too slight a degree of tenacity, and is liable to become easily chipped and 

 fissured. 



It was necessary, therefore, to employ some other material, and a solution 

 of gutta-percha in benzole was selected ; this was applied in a similar 

 manner over the object to be preserved. The pellicle left by the evapora- 

 tion of the benzole was tenacious, dense, and could be increased to any de- 

 sired thickness. Single layers were transparent, suiting admirably for layers of 

 fasciae. For the encasement of the adipose tissue, collodion was still employed. 



The thick coating, however, which it was considered necessary to apply upon 

 the muscular mass, was of course opaque ; hence, it became of importance to re- 

 sort to an artificial coloring process, and for this purpose, collodion stained with 

 the wood of the Pterocarpus santalinus, (the ordinary red saunders,) was found 

 to answer admirably. The color resulting imitated closely that of fresh muscle. 

 The preparation was then completed by the repeated application of copal and 

 shellac varnishes. . 



Dr. Brinton explained to the Academy, that he did not present his specimens 

 as tried and perfected preparations, for as yet they had attained the age of but 

 some twenty days ; but merely as evidences of the application of a new principle 

 to the preparation of anatomical objects. Time was required to test its value. 



Whether or not any internal decomposition could take place in consequence of 

 the retention of a residual amount of air, Dr. Brinton could not state; but he 

 doubted that such would be the case, to a degree sufficient to affect the contour 

 of the specimen. Should, however, such a result ensue with regard to the speci- 

 mens upon the table, still his experiments had shown that the process was ap- 



