Apri 7, 1923] 
pre-Cambrian studies in Canada until after the dis- 
covery of ore-bodies at Sudbury, Cobalt, and Por- 
cupine in Ontario. Meanwhile, on the United States 
side of the border such advance as was made was 
the outcome of studies connected with extensive and 
“poem developments in the mining of iron ore 
and copper ore in that region. Indeed, both in its 
inception and throughout its history the prime 
motive underlying the work of the United States 
Geological Survey has been an economic one; and 
that Survey furnishes an excellent example of the 
valuable scientific work made possible only by the 
great utility of the organisation by which it was 
carried out. Other examples could be given, and 
Dr. Miller mentions particularly that of South Africa, 
where the science of geology profited immensely as 
a result of the establishment of diamond-mining and 
gold-mining industries. 
Dr. Miller had no difficulty at all in showing that 
eology owes a great debt to the mineral industry. 
_ His address will be read with much interest by that 
_ ever-increasing band of workers who feel, as he feels, 
_ that science and art should be mutually helpful and 
not distrustful of one another, and that a genuine 
scientific worker does not necessarily sacrifice dignity 
_by carrying out investigations the results of which 
are likely to be useful. 



STRUCTURE AND ORIGIN OF THE PLANT GALL. 
_ Prof. Melville T. Cook devoted his address, as 
president of Section G (Botany), to the subject of 
lant galls, and thus rendered a service to the workers 
in a field where literature is very scattered. In 
America, as in Europe, this study has been shared 
between entomologists, bacteriologists, mycologists, 
and other students of plants, and a general com- 
prehensive account is difficult to find; from this 
address it appears that there is still much work to 
be done, progress probably having been delayed by 
the specialist angle from which each investigator 
_has approached the problem. 
The old idea that the gall arose as the result of a 
special fluid excreted by the insect as it punctured 
e plant has long been discredited ; but although it 
is known that the gall tissue develops pari passu 
with the growth of the larva from the deposited 
egg, there is very little information as to how the 
larva reacts upon the plant tissue and whether the 
effect is produced by mechanical or chemical agencies. 
_ The reaction evidently depends in part upon the 
plant tissue affected, and Prof. Cook lays great 
Stress upon the fact that it is usually only meri- 
stematic tissue which is stimulated to abnormal 
growth; but bearing in mind the conditions under 
_ which cork meristem arises in the plant as the result 
of a wound, it seems probable that in a living tissue 
the capacity for meristematic activity will usually 
be found in the proximity of the potential gali- 
former. 
Kiister, in 1911, divided gall tissues into abnormal 
growths, consisting only of parenchyma, the kata- 
tion of tissue, the prosoplasmas. Prof. Cook, and 
‘also Wells, have developed this original classifica- 
tion indicating that the more highly developed 
prosoplasm is a more specialised form of growth 
which has had its ‘‘ kataplasmic”’ stage; the most 
complex types, such as the Cynipid galls, actually 
showing differentiation into four zones arranged 
concentrically around the larval irritant. Galls of 
fungoid or bacterial origin are also discussed in the 
light of this description of types of insect galls, 
and it will interest British botanists to find that 
Prof. Cook has evidently an open mind as to the 
NO. 2788, voL. 111] 
NATURE 
plasmas, and growths undergoing further differentia- 
483 
analogy drawn by Dr. Erwin F. Smith between the 
crown gall caused by Bacteriwm tumefaciens and 
the malignant growths found in the animal. He 
is evidently inclined to regard Dr. Smith’s “ em- 
bryomas,” arising at a distance from the original 
infection, as due to the disturbance of normal 
functional activity in the host, just as in the case 
of the formation of aerial tubers upon the potato 
as the result of the attack of Rhizoctonia Solani. 
THE MininGc INDustTRY oF CANADA. 
Dr. J. B. Tyrrell selected the history of Canadian 
mining for the subject of his presidential address 
to Section M (Engineering). In such an address the 
details of so wide a subject cannot of course be 
dealt with, but Dr. Tyrrell gave a very clear outline 
of the general course of progress of the Canadian 
mining industry. Necessarily, in so doing he has 
included much interesting information on the develop- 
ment of Canadian metallurgy, for it is impossible 
to separate these two arts when tracing the history 
of either in any particular new country, any more 
than they can be divorced when considering the 
early history of human civilisation as a whole. 
The records of Canadian mining commence as 
early as 1576 with Frobisher’s attempt to find gold 
on the shores of the bay that now bears his name. 
Better success attended later efforts to work the 
commoner minerals, and the history of true mining 
in Canada may be said to date from the discovery 
of coal near Sydney, Cape Breton, in 1672, which 
laid the foundation of the important coal - mining 
industry and perhaps even more important iron 
and steel manufacture of the Maritime Provinces. 
Dr. Tyrrell chronicles the discovery of bog iron ore 
in the province of Quebec about the middle of the 
17th century, and the erection of a blast furnace to 
smelt this ore in 1737. So far as iron is concerned, the 
history stops with the erection of charcoal furnaces 
in Ontario in 1810, followed by another in 1813 in 
Norfolk County, which remained in blast until 1847. 
It is to be regretted that Dr. Tyrrell did not carry 
this particular industry somewhat further. An 
interesting chapter would be furnished, for example, 
by the attempts to utilise the iron sands along the 
north shore of the St. Lawrence: these were dis- 
covered in 1767, when a Mr. Molson of Montreal 
built forges of the Catalan type to smelt them: but 
his enterprise was commercially unsuccessful though 
he made good iron, and it closed down after a life 
of nine years. The same fate attended attempts 
made afterwards by others, among whom was Dr. 
Sterry Hunt. A charcoal blast furnace was erected 
early in the 19th century at Londonderry, Nova 
Scotia, where a brand of pig-iron, which at one time 
had a great reputation under the name of Acadian 
pig-iron, was smelted from ores consisting chiefly 
of brown hematite and ankerite. At this place 
the first coke blast furnace in Canada was built 
about 1876 by the Steel Company of Canada, Ltd. 
Afterwards attempts were made to utilise the interest- 
ing fossil ore of Nictaux in the Annapolis Valley, 
Nova Scotia, but now the important iron industry 
of this province relies upon the magnificent Wabana 
ore brought across from Newfoundland. 
Dr. Tyrrell describes well and clearly the modern 
developments in Canadian mining, which he dates 
from the construction of the Canadian Pacific Railway 
in 1885, and shows good grounds for his conclusion 
that in mining ‘‘ our country offers a field for ex- 
tensive and intensive research second to none in 
the world,” though he justly emphasises the need 
for a thorough scientific training for those who are 
to take the lead in future developments. 
