59 



But in this inquiry we must take care not to confound 

 raphides with ci-ystal prisms, sphoeraphides, and other 

 crystals. There will be endless confusion else. Their 

 distinctive characters are given, with far more details than 

 can be entertained at present, in the memoirs contributed 

 by me to the Annals of Natural History, the Micro- 

 scopicalJournal, and Seemanii'sJournaloJ Botany, from 1861 

 to 1866, and epitomized in the Popular Science Review for 

 1865-8. And I must beg to warn you against the very 

 maze of errors on this and other points of the subject 

 occurring in all the books on the Microscope with which 

 I am acquainted ; for in this department of phytotomy 

 confusion has been led round from compiler to compiler in 

 most admired disorder. 



The question will arise of the use of raphides and other 

 l-lant-crystals ; it has never been answered. But we have 

 now proveil one use of them in systematic botany, including 

 the fact that nature has regularly established in certain 

 plants a laboratory and storehuuse of these crystalline 

 calcareous salts ; while wc all know how valuable they are 

 as manure, and can now perceive how curiously and care- 

 fully the excess of them, more than has been expended in 

 the economy of the plant, is soon and periodically restored 

 to the parent soil, so that there may be no unnecessary loss 

 of a fertilizing matter. Hence we see a good reason why 

 the rotted leaves and other parts of such vegetables— « 5". 

 the Willow-herbs, Fuchias, and Duckweeds —as abound in 

 raphides, should be carefully husbanded by the gardener for 

 his composts. These crystals are surely also useful, if not 

 necessary, as part of the food of many animals, and some- 

 times as medicine for man. The commonest Duckweed 

 abounds in raphidian cells and starch-granules ; and I have 

 found it, presenting its true cell -characters, in the 

 stomachs of water-fowl and water-rats. Thus even this 

 abject and despised weed is plainly useful in the economy 

 of nature, and we could hardly imagine a better adjunct 

 to the aliment of the young growing animal than the 



