B.—CHEMISTRY. 45 
liquids themselves, this gas is absorbed much more freely by chlorophy}} 
hydrosols than by other colloidal solutions, a maximum assimilation of 
two molecular proportions to one magnesium atom being reached, when 
pheophytin is precipitated :— 
C55H720;N4Mg + 2CO. + 2H20 = C;;H740;Ny+ Mg(HCOs)s. 
Prior to this change, which is the first stage appearing in a controlled 
disruption of chlorophyll-a by mineral acids, there is produced an 
intermediate compound resembling a hydrogen carbonate in which the 
metal retains a partial grip on the nitrogen :— 
igo | Lscce Aceh 
—N.C:0C.C.N.C— =N.C:0.C.NH.C— 
a | eit | 
ee Mg +CO + H,0 === “s Mg.0.CO.H 
ee Soh ge 
=N.C:C.C.N.C— =N.0:0.0.N.C— 
ieee || Haire 
‘It is suggested that leaf-green unites with carbon dioxide by similar 
mechanism, and that the action of light on the above compound trans- 
forms the carbonic acid, into an isomeride having the nature of a 
peroxide such as per-formic acid, H.CO.O.OH, or formaldehyde 
' O 
peroxide, HO. CHC | P 
' Anthocyans, the Pigments of Blossoms and Fruits. 
‘Since the days of Eden, gardens have maintained and extended 
their silent appeal to the more gentle emotions of mankind. The 
subject possesses a literature, technical, philosophical, and romantic, 
at least. as voluminous as that surrounding any other industrial art, 
and the ambition to cultivate a.patch of soil has attracted untold 
millions of human beings. Amongst manual workers none maintains 
a standard of orderly procedure and patient industry higher than that 
of the gardener. Kew and La Mortola defy the power of word-painters 
_ to condense their soothing beauty into adequate language, whilst that 
wonderful triangle of cultivation which has its apex at Grasse almost 
might be described as industry with a halo. 
_ To the countless host of flower-lovers, however, it is probable that 
Grasse is the only connecting-link .between chemistry and _ their 
cherished blossoms, they being dimly aware that the ingredients of 
some natural perfumes have been imitated in the laboratory. The 
circumstance that identical products of change are generated by the 
plant, however, and form but one section of the numberless chemical 
elaborations which proceed before their eyes escapes them because it 
has been ordained that chemistry is to occupy a backwater in the flood 
of knowledge. Let us hope that before another century has passed 
this additional charm to the solace of a garden may be made more 
generally accessible. 
