ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 717 



from plate cultivations are represented nnder a low power, and those 

 from test-tube cultivations of the natural size. 



As the authors of the work are Koch's assistants, their work may be 

 accepted as representing micro-organisms faithfully. 



Detecting Alterations in Manuscripts.* — As an accessory to the 

 Tise of the Microscope, photography is recommended by Mr, G. G. 

 Eockwood. He has for years been in the habit of photographing manu- 

 scripts, models, books of accounts, cheques, and drafts, Avhenever their 

 genuineness was questioned. The process sometimes makes legible 

 figures, amendments, and alterations which even the Microscope does 

 not fully bring out. This is due to the extreme sensitiveness of photo- 

 graphic plates to shades of colour. With the new " auto-chromatic " or 

 colour- sensitive plates almost imperceptible stains on old yellow paper 

 have been made clear and legible. 



Cock, G. B. — The Microscope in the Mill. Queen's Micr. Bulletin, VI. (1SS9) p. 10. 



* Amer. Mon. Micr. Journ., x. (1889) p. 126. 



