SUPPOSED FALLACIES OF THE MICROSCOPE. 39 



the foundation of all our scientific knowledge of these very inte- 

 resting forms. Although the curious phenomenon of " conju- 

 gation" had been previously observed by Miiller, yet its con- 

 nection with the function of Reproduction had not been even 

 suspected by him ; and it was by Vaucher that its real import 

 was first discerned, and that its occurrence (which had been re- 

 garded by Miiller as an isolated phenomenon, peculiar to a single 

 species) was found to be common to a large number of humble 

 aquatic forms of vegetation. But little advance was made upon the 

 discoveries of Vaucher in regard to these, save by addition to the 

 number of their specific forms, until a fresh stimulus had been 

 given to such investigations by the improvement of the instru- 

 ment itself. At present, they are among the most favorite ob- 

 jects of study among a large number of observers, both in this 

 country and on the Continent ; and are well deserving of the 

 attention which they receive. 



Less real progress seems to have been made in Microscopic 

 inquiry, during the first quarter of the present century, than 

 during any similar period since the invention of the instrument. 

 The defects inseparable from its original construction, formed a 

 bar to all discovery beyond certain limits ; and although we are 

 now continually meeting with new wonders, which patient and 

 sagacious observation would have detected at any time and with 

 any of the instruments then in use, yet it is not surprising that 

 the impression should have become general, that almost every- 

 thing which it could accomplish had already been done. The 

 instrument fell under a temporary cloud from another cause ; 

 for having been applied by Anatomists and Physiologists to the 

 determination of the elementary structure of the .animal body, 

 their results were found to be so discordant, as to give rise to a 

 general suspicion of a want of trustworthiness in the Microscope, 

 and in everything announced upon its authority. Thus both 

 the instrument and its advocates were brought into more or less 

 discredit ; and as they continue to lie under this, in the estima- 

 tion of many, to the present day, it will be desirable to pause 

 here for awhile, to inquire into the sources of that discrepancy, to 

 consider whether it is avoidable, and to inquire how far it should 

 lead to a distrust of Microscopic observations, carefully and saga- 

 ciously made, and accurately recorded. 



It is a tendency common to all- observers, and not by any 

 means peculiar to Microscopists, to describe what they believe and 

 infer, rather than what they actually witness. The older Micro- 

 scopic observers were especially liable to fall into this error; since 

 the want of definiteness in the images presented to their eyes, 

 left a great deal to be completed by the imagination. And 

 when, as frequently happened. Physiologists began with theorizing 

 on the elementary structure of the body, and allowed them- 

 selves to twist their imperfect observations into accordance with 

 their theories, it was not surprising that their accounts of what 



