ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 823 



which are insoluble in petroleum ether, but soluble in alcohol. In 

 pouring a solution in concentrated alcohol upon water, the chloro- 

 phyll is gradually precipitated by diffusion, but it takes the form of 

 brown flakes, which appear completely changed. On replacing the 

 water by alcohol at 50^ the chlorophyll is precipitated in deep green 

 flakes without any evidence of crystallization ; but the product thus 

 f»btained is very impure. Chlorophyll is very stable in the presence of 

 bases, behaving like a true acid and giving compounds which appear 

 to be very well defined. In order to obtain in the crystalline state 

 the combination of chlorophyll and soda, alcohol may be added to 

 the aqueous solution of that compound. On evaporating over lime 

 under a bell-glass, the lime absorbs aqueous vapour, and the alcohol 

 becomes more and more concentrated until it deposits needles of a 

 very deep green, which appear almost black ; they are very soluble in 

 water, and present all the characters of a perfectly definite compound. 



Crystals in the Leaves of Leguminosse.* — Prof. J. P. Borodin 

 has examined the distribution of the crystals of calcium oxalate in 

 C60 species of Leguminosfe. In the Mimoseas their occurrence is 

 very constant, in the form of solitary crystals disposed parallel to the 

 veins. In the Caesalpiniefe the distribution is the same, but in 

 addition there are clusters of crystals scattered through the paren- 

 chyma of the leaf. These occur again in the Eosace^e, but not in the 

 Papilionace^. In the Papilionaceae there are three principal types : — 

 (1) Crystals altogether wanting: — the Genisteae, many Galegeae, as 

 Astragalus and Colutea, and some genera in other groups. (2) Clino- 

 rhombic crystals along the veins: — the Viciese and Trifolieas ; some 

 Phaseolefe and Galegeae have clinorhombic crystals scattered through 

 the parenchyma. (3) Clinorhombic crystals in groups in the epider- 

 mis : — Dioclea and Canavalia ; in StylosaniJies the crystals lie in the 

 membrane of the ejiidermis. When crystals are wanting in the leaves, 

 they are deficient also in the stem. 



Secreting Canals of Plants. f — In pursuance of previous investi- 

 gations on the same subject,^ M. P. van Tieghem gives details as to 

 tlie nature and arrangement of the secreting canals in a large number 

 of natural orders of Dicotyledons. 



In the Labiatiflora^ (suborder of Compositaa), when secreting 

 canals occur, their structure and arrangement correspond to that in 

 the suborders liadiiflora) and Tubuliflorse. In tlic Compositfe taken 

 alt^jgether, the secreting apparatus occupies two different regions 

 according to its nature ; when composed of oleiforous canals it belongs 

 to the endoderm ; when composed of laticiforous cells, whether isolated 

 or forming a network, it belongs to the liber in the root, to the 

 pcricycle in the stem and leaves. 



Tlic Dipsacacca> resemble the Tubuliflora) in the presence and tho 

 pofiition of the lacticiferous cells, but differ from all Composita) in 



• SB. Intemat. Congress f. Bot. u. Gartenbau, St. Petersburg, May 1884. 

 See Bf.t. Ccntralbl, xxi. (IHS.")) pp. 222 and .'$.51. 

 t Ann. Bci. Nat.— Bot., i. (1H8.')) pp. .O-DG. 

 J Sec- tliio Journal, iv. (1884) pp. 707, 770. 



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