PKEFACE. 



in systematic works, being unavoidably those of individuals, 

 and not of species, have been far too much relied on as aiford- 

 ing means of identification. 



The other great obstacle has been the immense number of 

 works, and especially of periodicals, we have had to consult : 

 120 authors' names are attached to the 430 species described, 

 and the completion of the ' Flora Indica' will require a re- 

 ference to upwards of 1000 volumes. We would now there- 

 fore call the attention of our fellow-botanists to the fact, that 

 the time is rapidly approaching, when the difficulty of ob- 

 taining access to the necessary periodicals must render the 

 effectual study of botany impossible ; and that the practice of 

 naturalists sending their several papers to diflferent periodi- 

 cals, and above all to local ones, or to such as embrace many 

 branches of science, is one of the greatest obstacles to the 

 study of natural history in the present day. We have found 

 it impossible to obtain access to several journals of local or of 

 ephemeral interest, and it would be well if isolated naturalists 

 paused before they sought to establish such, or to send their 

 contributions where they must be inevitably overlooked. 



After a careful review of the state of botanical literature, in 

 this country at any rate, we have no hesitation in saying that 

 the Transactions of well-established Associations for the fur- 

 therance of natural science, difPuse most effectually the labours 

 of naturalists. This is because these societies are supported 

 by persons whose interest it is to disseminate their publica- 

 tions at the smallest possible delay and cost ; and, what is of 

 great importance, all papers communicated are subjected to 

 a system of supervision before publication, which ensures their 

 being worthy of it. 



We need not say, that while urging the propriety of cen- 

 tralization within reasonable limits, we are far from wishing 

 to see the natural and physical sciences entirely separated. In 



