SUMMARY OF CURRENT RESEARCHES RELATING TO 
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system, and is arranged for very delicate focusing. Both the coarse 
and fine adjustments are provided with extra large milled heads to 
afford a firm grasp. The stage is of the Nelson horse-shoe shape, and 
Fig. 1. 
large enough to take culture-plates ; this form is adopted for lightness 
and for the facility it gives in feeling the working distance of the 
objective. Instead of the usual spring clips, a sliding frame is provided 
