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SUMMARY OF CURRENT RESEARCHES RELATING TO 



a much slower impression than the rest of the preparation, which 

 gives free passage to all the green rays. More contrast is thus 

 obtained and a very distinct photograph produced. 



Beck's "Complete" Lamp. — For pathological and physiological 

 investigation, as also for many other branches of microscopical 



Fig. 107. 





research, a lamp more delicate in its adjustments and giving a 

 greater control over the light than those ordinarily in use is requisite, 

 and Messrs. Beck have therefore constructed a lamp whereby more 



