amlFniit of Vegetables, SfC. 41 



I have pi-oduced the same effect upon filbercl- or hazel-nut 

 bushes, by takhig awav the male catkms before the stigmata 

 were evolved. The well-known fact of clusters of empty nuts, 

 often depends upon the destruction of their neighbouring cat- 

 kins, and I have seen it extensively produced by a dormouse. 

 A series of experiments, which 1 began some years ago, upon 

 the different freezing capacities of viscid fluids, induce me to 

 conclude, that many, if not all, of the vegetable powers ot resist- 

 in<' con-^elation, depend on the same or snnilar physical causes. 

 I was led to this iiupiirv by noticing the diiliculty ot Ireezing 

 treacle, paste, dissolved starch, and some oils, as those Irom 

 the nut and almond, and the most part ot essential oils, ihe 

 remarkably low temperature required to freeze these viscid com- 

 pounds, directed my attention to the composition ot the juices, 

 and to the parenchymatous parts of the willow, the holly, the 

 misletoe, and the alder; and also to the physical composition 

 of many evergreens. Some of those, as the box, extend over a 

 wide ran^e of climates, and others which have been transported 

 hither from mild regions, bear the frosts of this country with 

 impunity. The causes of this capability in plants ot enduring 

 such vicissitudes, is worthy of research, because the results 

 may, as before intimated, teach us how to ascertain those viva- 

 cious properties, both in exotics, and in the new varieties ot 



our own culture*. . . , , , ^ i 



The advancement of vegetable physiology has been too long 

 retarded by a continued effort to force upon it analogies with 

 the structure and offices of animal organs The ways ot na- 

 ture are, however, not limited by confined rules like those ot 

 man: her diversities are endless; and she is not obliged to 

 work by any methods of system, of analogy, or ot classitica- 

 tion. Such methods are indeed great (it not indispensable) 

 lielps to human knowledge; but when we attempt to impose 

 them upon the works of creation, we otten darken and dull 

 the evidences of our senses, and contuse the oi)erations ot 



'^'^^ The leaves of iilants have Ijeen compared to the lungs of 

 animals, upon a 'few slender anaU.gies ; but the add.tio.ud 

 <,flices known to be performed by leaves, show llK-m to be also 

 allied to the digestive and assimilating organs. Tsor is it at all 



* TI.e ccncnOitv of wh.tcr l.mls are admirably a-U-i.tcl for rcsistinn; frost 

 ,.V ti.' ".n"K.tc.l':t...l dry stale of their s,>.,„,y snl.sU.n.e ; ^^^^^ 

 l.„r,e-cl.csn'ut are coated with a vise., v'-'nush nv n -^ n|K t. hie 

 run, „r dew. Most <.r the other spee.es oi ^^""Y, . 'Vom So .t' by 

 tected apiinst evaporati.... fro... w.th.n, a..d ...o.stu.c from without. i.y 

 deiibe shelly coveriiitis. 



\'ul. (JO. No. 2!; 1 . M!J 1 H22. F "'"••^^- 



