234 DR. CARPENTER, ON THE MICROSCOPE 



by the aid of single lenses, the Compound Microscope having been only 

 occasionally applied to, for the verification of what had been previously 

 worked out, or for the examination of such minute details as the power 

 employed did not suffice to reveal. 



" But it should be urged upon such as are anxious to do service to 

 Science, by ! the publication of discoveries which they suppose themselves 

 to have made with comparatively imperfect instruments, that they will do 

 well to refrain from bringing these forward, until they shall have obtained 

 the opportunity of verifying them with better. It is, as already remarked, 

 when an object is least clearly seen, that there is tnost room for tne exercise 

 of the imagination ; and there was sound sense in the reply once made by 

 a veteran observer, to one who had been telling him of wonderful discove- 

 ries which another was said to have made ' in spite of the badness of his 

 Microscope,' — ' No, Sir, it was in consequence of the badness of his Micro- 

 scope.' If those who observe, with however humble an instrument, will 

 but rigidly observe the rule of recording only what they can clearly see, 

 they can neither go far astray themselves, nor seriously mislead others." 



The description of apparatus is followed by a very com- 

 plete account of the various methods adopted for mounting 

 and preparing objects. 



The second part of the work consists of an account of the 

 various forms of animal and vegetable life, which are the 

 subjects of microscopic research. In this department it was 

 to be expected that Dr. Carpenter would dis])lay his great 

 knowledge of Biological phenomena, and few persons, how- 

 ever profound their knowledge of particular departments of 

 anatomical research and physiological laws, will fail to read 

 these chapters without adding to their stores of knowledge and 

 widening their sphere of thought. 



This section of the work is almost a complete resume of 

 the present state of our knowledge of the histology, repro- 

 duction, and development of the vegetable and animal king- 

 dom ; and Dr. Carpenter, by his general remarks, has given a 

 consistency and unity to these subjects, which will recommend 

 his book where microscopical research is not the object of 

 study. As a specimen of the manner in which these general 

 subjects are treated, we give the following : — 



" 279. The Reproduction of the Rotifera has not yet been completely 

 elucidated. There is no instance, in this group, in which multiplication 

 by gemmation or spontaneous fission is certainly known to take place ; but 

 the occurrence of clusters formed by the aggregation of a number of indi- 

 viduals of Conochilus, adherent by their tails, and enclosed within a common 

 lorica, would seem to indicate that these clusters, like the aggregations of 

 Polygastrica, Bryozoa, and Tunicata, must have been formed by continuous 

 growth from a single individual. The ordinary method of multiplication, 

 however, is commonly supposed to be by a proper generative act ; as dis- 

 tinct sexes have been discovered in several individuals, and the act of 

 sexual union has been witnessed. The condition of the male of the re- 

 markable genus described by Mr. Dalrymple (loc- cit.) is a most extraor- 

 dinary one ; for it possesses no mandibles, pharynx, oesophagus, stomach, 

 nor hepatic glands ; having, in fact, no other organs fully developed, than 



