THE SCIENCE OF MICROSCOPY. 309 



That is to say, he is an anatomist, pathologist, naturalist, &c., 

 before all things — a microscopist, only so far as the microscope is 

 a necessary means to his end.* And thus the science of microscopy 

 falls to the ground by the divorce of practice from theory, while in 

 the absence of equal experience, and of standard rules of interpre- 

 tation, individual authority usurps a temporary lead. The observer 

 who is biassed by arbitrary and conflicting opinions of the day, or 

 by the nature and direction of his own studies, will be uncertain 

 or arbitrary in noting and verifying his "'facts.'' And zealous as 

 he may be for the advancement of the science which he is helping 

 to "create," he will fail to raise the status of practical microscopy 

 as a '^ science of observation,'' so long as he avoids the appeal to 

 optical law or neglects its safe-guards in his interpretation of the 

 objective images before him, the physical conditions and significance 

 of which no mere inspection will enable him to divine. 



The service rendered to science by the microscope may be 

 considered from two distinct but equally essential points of view, 

 according as we look to (i) the performance of the microscope as 

 an optical instrument, or (2) to the accuracy of the observations 

 made with its help. Under the first heading falls the technical 

 estimate of performance of every microscope employed for scientific 

 research. But beyond this, its narrowest sense, there lies the 

 wider field of the general theory of the microscope, with that of 

 the illuminating apparatus and the rationale of its application. The 



* Its claim to existence is ignored in the following terms by a writer in the 

 American Quarterly Micr. Journal — "While we plainly deny the claims of 

 microscopy to the position of a science, we as strongly urge its claims as an 

 invaluable adjunct in many studies." 



Of what real value asks the same writer {Ajner. Quart. Micr. Journal) 

 would all its revelations be to us, without the systematic grouping of facts 

 and knowledge which comes with the development of these sciences (histology, 

 pathology, &c.,) some of which microscopy has created (!) 



One is tempted to ask of what use these revelations might be to the sciences 

 created or built up by them if there were no system of observing, no rule 

 ia verifying, no restraint of science in interpreting them. 



