1886. | Microscopy. 1073 
cylinder. Butin reality, with objects of ordinary size, this error 
is not apparent, and even under a high magnifying power there is 
no perceptible difference between sections cut by this microtome 
and those cut by ordinary slide microtomes. 
EMBRYOGRAPH FOR USE WITH ZeEIss MıcroscorpeEs.—This piece 
of apparatus, which is the work of Adam Pfeifer, the instrument- 
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maker of the Biological Laboratory of the Johns Hopkins Uni- 
versity, renders the Zeiss-Oberhausen camera available for draw- 
ing objects under very low magnifying powers. It consists, first, 
of a collar fitted to the arm of the microscope, and furnished with 
a short draw-tube, which can be placed with the objective either 
above or below the arm; and second, of a vertical rod, supported 
a 
