SCIENTIFIC SUMMARY. 
423 
none approaching completeness on the vegetation of the country that is 
probably richer in vegetable products than all the rest of our dependencies 
put together. The present volume contains comparatively little that is abso- 
lutely new — that is to say, descriptions of new genera and species j but its 
chief value is in being a compendium, so far as it goes, of all the plants 
known to grow in the country, written in English. It contains the poly- 
petalous families from the Ranunculaceae to the end of the Sapindaceae, 
embracing descriptions of 442 genera and 2,250 species. Dr. Hooker’s 
“ Student’s Flora of the British Islands” has been followed in the style and 
arrangement of the matter, which has caused a considerable saving of space, 
as compared with similar works. Several botanists have contributed to the 
present volume ; but even with the united labours of half-a-dozen contri- 
butors, the completion of the work cannot be effected in less than as many 
years. The species number from 12,000 to 14,000, scattered over an area 
of 1,500,000 square miles, representing every variety of climate. 
The Chemistry of Thormium tenax . — Professor S. Church has worked 
this out, among various others that he has written upon in “ The 
Journal of Botany.” He says : a The two reports on the chemistry of 
Thormium tenax which I have addressed to the Flax Commission of New 
Zealand contain many points of interest in connection with this subject. 
These reports will shortly be published in the form of an abstract, but in 
the meantime I may select from them the following curious observations as 
to the effect of water at a high temperature on tissues containing lignose, 
and on the indifference of cellulose to such treatment. When pure cellulose, 
prepared from cotton as just described, was boiled for twelve hours with 
distilled water, it gave up no appreciable amount of organic matter to the 
water, which did not acquire an acid reaction. Even in a sealed tube, at a 
temperature maintained at 150° C. for four hours, water was almost without 
effect on cotton. But with Phormium fibre a small quantity, about 4 per 
cent., of an acid yellow extract was obtained even by simple ebullition with 
water at 100° C. ; while at 150° to 160° O. water causes so great a change in 
the material that it dissolves in quantities amounting in different specimens 
to 19, 24’4, and even 33*3 per cent, of the dry fibre taken. The nature of 
the products formed has been in great measure investigated, a kind of sugar 
and an acid body occurring amongst them. But the point to which I wish 
now to direct attention is the test which water at high temperature affords 
of the presence or absence of the so-called secondary deposits. We know 
that lignose is coloured yellow, brown, or red by strong nitric acid, and that, 
in the purest state in which it has yet been separated, it is richer than 
cellulose in carbon by about 10 per cent. But the employment of water 
under pressure and at different temperatures above the boiling point may 
enable us to take a further step in this inquiry, and to ascertain whether 
lignose is a mixture or a homogeneous substance. And we may then hope 
to obtain by other methods of research some insight into its chemical con- 
stitution and its physiological production.” 
