WITH THE MICROSCOPE. 1 87 



the most convenient are those suggested by Mr. Piper, and sold 

 by Mr. Highley, Mr. Collins, and others. They are made for two 

 three, six, and twelve dozen specimens, costing respectively 2s. 6rf., 

 3 jr. 6//., 5-r. 6d., and los. Cases made of deal are also arranged on 

 the same plan. 



233. Of making Observations upon Specimens in the Microscope. 

 If, upon examination, a specimen does not appear to the observer 

 to justify the description or delineation which some observer has 

 given of a similar structure, he must not too hastily infer that the 

 author has been recording the results of his imagination rather than 

 observed facts. The conclusions which have been arrived at are 

 probably the result of a very long and patient investigation, deduced 

 from examining specimens, perhaps, many under very different circum- 

 stances, after the application, perhaps, of various chemical reagents, 

 and after ascertaining the effect of different refractive media. From 

 the remarks already made, some idea may be formed of the many 

 different operations which are necessary to demonstrate conclusively 

 the anatomy of a single tissue. The observer must not, therefore, 

 be too hasty in deciding upon the nature of an object in the micro- 

 scope ; neither must he infer that what he has not been able to see 

 does not therefore exist. His eye and mind will require much 

 careful education before he can hope to be able to form a correct 

 opinion. 



Some, however, fall into an error of another kind, but not less 

 detrimental to forming habits of correct observation. Led away by 

 their imagination, .they think they see everything which has been 

 delineated, or which they have heard described ; the observations of 

 authors appear to be confirmed, and, in expressions closely 

 resembling the original, while in truth their own assertions are 

 merely reiterated in favour of their own doctrines, without any real 

 confirmation of the accuracy of their views being advanced. In. 

 this manner errors have been confirmed and propagated to an 

 extent almost incredible, and it may require years of laborious 

 investigation to overthrow statements which never resulted from 

 actual observation, which were erroneous from the first and ought in 

 fact never to have been received. Sometimes a mere idea, taking for 

 its ingenuity and novelty, but having no foundation in fact, is seized 

 upon by a number of persons, and supported by so many assertions 

 wrongly called observations, that it is soon received as true, and is 

 perhaps believed in for years, until at last some one reinvestigates 

 the whole question, and at length demonstrates the absurdity of the 

 doctrine. 



Of the Importance of Making Sketches. Of the great importance 



