SCIENTIFIC SUMMARY. 
309 
whilst others more or less aberrant are more or less restricted to particular 
localities, the same varieties not occurring in disconnected stations with pre- 
cisely the same combinations of character; and in the same proportions 
local and representative varieties and sub-species are being formed, but have 
not yet obtained sufficient advantages to prevent their being kept in check 
by their inter-communication (and probable cross-breeding) with their more 
robust type. The British rubologist or rhodologist transported to the south 
of France or to Hungary will still find one, or perhaps two or three, forms 
of bramble and dog-rose with which he is familiar ; but if he wishes to dis- 
criminate the thirty or forty varieties or sub-species upon which he has 
spent so much labour and acuteness at home, he will find that he must 
recommence with a series of forms and combinations of characters quite new 
to him. The species is still the same ; the varieties are changed. 
A Pomological Dictionary . — The Athenceum states that M. Andre Leroy, 
of Antwerp, is engaged on a Dictionary of Pomology ; three large volumes 
are ready, and treat of pears, apples, quinces, service-trees, and medlars. 
Two more volumes will complete the work, one of which will treat of 
stone-fruits, the other of grapes and miscellaneous fruits. Each species of 
fruit is treated in an elaborate way, and to the mode of its culture is pre- 
fixed a history of its culture (besides several types of each variety— 915 
varieties of pears are described), and each description is accompanied by a 
woodcut. 
Double- Flowers and Variegations. — M. Morren, of Liege, has established 
the fact that (contrary to a supposed law) double-flowers and variegations 
can occur together on the same plant. 
CHEMISTRY. 
The Detection of Logwood Colour in Wine. — This is an important applica- 
tion of chemistry to hygiene, and may interest some of our readers. In the 
Journal de Pharmacie for April, M. Lapeyrere states that, while studying 
some of the properties of the colouring principle of logwood, he found that 
the hematine it contains yields a sky-blue colour with salts of copper. In 
order to apply this test to wines for detecting if they are doctored with log- 
wood, it is only necessary to place strips of good filtering-paper, Swedish 
being preferred, into an aqueous solution of neutral acetate of copper, and, 
after drying, use one of these slips to test the wine suspected to be adul- 
terated with logwood colour, by dipping the paper into the wine ; and, on 
removing it from that fluid, care should be taken to cause the adhering drop 
of wine to flow backwards and forwards over the paper, which is next 
rapidly but carefully dried. If the wine be as it naturally ought to be, the 
colour exhibited after drying will be grey, or rose-red greyish ; but, if log- 
wood is present, the tinge will be distinctly sky-blue. 
The Homologues of Schweinfurt Green. — In a short paper, communicated 
by the Chemical Neivs (June 10), Mr. P. S. Strahan, B.Sc., says he has 
recently found that, if cupric formiate, butyrate, or valerianate be substi- 
tuted for cupric acetate in the process for the manufacture of Schweinfurt 
