REPORT ON THE DIVISIONS OF TEXTILES AND MEDICINE AND THE 

 SECTIONS OF WOOD TECHNOLOGY, ORGANIC CHEMISTRY, AND 

 FOOD. 



By F. L. Lewton, Curator of Textiles. 



COMPARISON OF INCREMENT OP SPECIMENS OF 1922-23 WITH THAT OF 1921-22. 



The accessions received during the year number 55 (including 

 2 joint accessions with other departments) , and in addition part of 

 an accession covering 1,145 specimens which was recorded three 

 3'^ears ago in the war collection:.-. 



The entries covered by the above accessions number 2,141, 651 

 less than were received in the fiscal year 1922. The greater part of 

 these entries was due to a transfer of specimens from the division 

 •of history to the division of medicine. The total number of en- 

 tries may be divided into five groups as follows : Textiles 137, medi- 

 cine 1,292, wood technology 192, organic chemistry 501, and foods 

 19. Each group with the exception of medicine and chemical prod- 

 ucts showing less entries than last year. 



The additions to the collections assigned to these divisions and sec- 

 tions consist of specimens not heretofore represented in the Museum 

 and taken as a whole are believed to be as valuable as those received 

 last year. 



ACCKSSIONS OF IMPOUTAXCI^. 



The most important accession of the year was a series of specimens 

 prepared and contributed by the E. I. du Pont de Nemours & Co. 

 (Inc.), of Wilmington, Del., illustrating the chemical and fabrica- 

 tion processes involved in making Pyralin, a pyroxylin plastic 

 which is very similar to celluloid. The word celluloid brings to 

 mind many statements of explosions and fires caused by this mate- 

 rial. But by scientific research, this important class of plastics has 

 been rendered non-explosive, while still retaining the disadvantage 

 of being inflammable when exposed to a flame or excessive heat. 



This series of specimens consists of three parts: the first illustrat- 

 ing the chemical processes involved in changing white rags into 

 tissue paper, nitrating it lO make pyroxylin, then mixing this with 

 camphor, dyes, and denatured alcohol to produce the pyroxylin 

 plastic material known as Pyralin, which is then rolled into thick 

 sheets from which sheets are sliced as thin as desired. The second 

 section illustrates the important steps in fabricating from sheets of 

 67132—23 8 103 



