RECORDS. 



115 



- '<i 



by some one not entirely familiar with the snbject, it not infreqnentl)' happens that 

 the statements in the paper which have been omitted from the aljstract as unim- 

 portant prove in the end to be the essential ones so far as the owner of the abstract 

 is concerned. For this reason, when the\' are within reach, the writer preters to 

 consult the original papers and to save for orig-inal work the time consumed in 

 making long abstracts. When they are rare, freqnenth' needed, and only to be had 



by Ijorrowiug, the writer has sometimes 

 photographed the more essential parts. 

 In one instance a pamphlet was bor- 

 rowed from Europe for this purpose. 



For the exact measurement of col- 

 onies, etc., a strip of ]:ilate glass 35 cm. 

 long and ruled into 350 mm. spaces 

 may Ije had from Carl Zeiss, and will 

 be found very C(jnvenient (fig. 102). 



Steel rules of an)' size and of \'er^' 

 excellent workmanship, graduated ac- 

 cording to the ICnglish or the metric 

 s)Stem in aiiv degree of fineness, ma)- 

 be had from the L. S. Starrett Com- 

 pau)', Athol, Mass. Two of these ndes 

 much used b)- the writer are, respec- 

 ti\eh', 12 inches and 30 centimeters 

 long. They are one inch wide and 

 al)out three sixty-fourths of an inch 

 thick. The^• are graduated on both 

 sides, the metric rule into centimeters, 

 millimeters, and one-half millimeters, 

 and the English into inches, hah-es, 

 quarters, eighths, sixteenths, thirty- 

 seconds, and sixty-fourths. 



Stage micrometers made bv Zeiss 

 are recommended for the finer measure- 

 ments. These lia\-e i millimeter 

 di\'ided into tenths, twentieths, and 

 one-huudredths very accurate!}'. All 

 the magnifications of microscopic 

 objects figured in this book are recorded in terms of such a micrometer. After the 

 di-awing has been made it is customary to substitute for the section-slide this stage 

 micrometer and throw the image of some portion of the ruled scale on the paper 





'^^•Siia... ^ 



I "iw»iri»in*i'iii ^.^^^' 



102.' 



*FiG. 102. — Green cucumber soft-rotted h_\- Bacillus aroiiJcoc. Contents emptied out and skin 

 filled with water and so photographed, 3 days from date of inoculation, wliich was by means of a 

 few needle-pricks. The fruit was kept at about 2S° C. The black bands are pencil marks on the 

 millimeter rule placed inside. The numerous small dark sputs are denser bits of tissue which did 

 not wash free on rinsins out the sack with water. At the left drops of water may be seen oozing 

 Uirough the skin and falling. Photograph, nearly natural size, by Townsend. 



