METHODS OF RESEARCH: CATALOGING AND FILING 131 



Standard library cards are recommended for the literature 

 catalogues. These should be of good size so as to admit of a 

 short summary of contents, if thought desirable. They may be 

 typewritten or else written in black ink and in a handwrit- 

 ing plain as print. For various other catalogues smaller cards 

 are sufficient. We keep an index of negatives, of paraffin- 

 embedded material, of culture media, of stock cultures, etc. 

 Our stained sections are filed in Pillsbury boxes, standing on end 

 in deep drawers. The paraffin block number is written on the 

 end of each box, and sections of all the hosts attacked by a para- 

 site are filed together under the name of that parasite. 



Our negatives are placed in strong paper negative bags and 

 filed in deep drawers. They are arranged alphabetically ac- 

 cording to the species name of the parasites, with lettered guide 

 boards separating the photographs relating to the different 

 parasites, and the photographs of each subject are numbered 

 serially on the face of the envelopes in red ink. 



Each negative bag has all necessary data written on it, but 

 this is not enough since various persons handle these negatives 

 and it is extremely easy to get the negative covers misplaced, 

 so that often after years have elapsed one is in great uncertainty 

 as to which belongs to which. I make it an invariable rule, 

 therefore, to write all necessary data on the margin of the nega- 

 tive itself, carefully selecting a place where the writing will not 

 interfere with the printing. In fact, I consider a negative with- 

 out such a record on it as worthless, no matter how good it is in 

 all other respects, because it is like a natural history specimen 

 whose locality has been lost. 



Negatives should never be filed without covers since if they 

 are on glass they are certain to become scratched or broken. 

 It gives me the shivers to see the way in which some scientific 

 men treat negatives. 



