5138 
tion was to obtain some first-hand information con- 
cerning the blood changes in workers in lead, 
especially as regards the significance of the presence 
of basophile granules in the red corpuscles (the 
‘erythrocytes ponctués’’ of French writers), and the 
conditions under which they occur. 
The men examined were all adult males. Most of 
them were employed at the works of the Chloride Elec- 
trical Storage Co. at Clifton Junction, in various ways 
involving contact with lead. Three men were un- 
doubted cases of lead-poisoning, not employed by the 
Chloride Company, but sent to the works to obtain 
bath treatment. 
The conclusions arrived at were as follows :— 
(1) The presence of basoohile granules in the blood 
of lead workers affords very strong evidence of lead 
absorption, but in itself is no absolute proof of lead 
poisoning. It would appear wrong to exclude such 
cases from following their ordinary work, but they 
should be regarded as a special class, and kept under 
close observation. The knowledge of the existence of 
such cases in a factory would certainly facilitate the 
work of inspection. 
(2) Blood examinations are of great value in cases 
where the clinical symptoms are doubtful, and in 
cases of suspected malingering or imaginary illness. 
In such cases a positive finding would at all events 
go to show that. lead absorption had occurred. A 
negative result is of less significance, though it has a 
certain value. 
Dr. S. Rideal, of London, in a paper read before the 
Domestic Hygiene Section of the congress, discussed 
the use of paper utensils in the home as a sub- 
stitute for glass and china or earthenware. The argu- 
ment for the use of paper plates, cups and saucers, 
which can be destroyed after use, was based chiefly on 
the fact that recent scientific investigation has proved 
that cups taken from schools, stores, and hotels have 
been found infected with several pathogenic forms of 
bacteria (including those of diphtheria, pneumonia, 
and influenza), even when supposed to be clean and 
ready for use. At one of the largest hospitals there 
is a regulation that all crockery, cutlery, glass, etc., 
should be rinsed in a disinfectant before being used 
again. In these days of typhoid and diphtheria ‘‘ car- 
riers,” the public are entitled to expect the adoption 
of similar precautions in places of refreshment; but 
this, of course, involves expense and labour. 
Samples of the following articles, made in paper, 
were exhibited at the close of the address, which 
aroused much interest and a keen discussion :— 
Cups: automatic dispenser; collapsing. Plates, 
table-covers; handkerchiefs; towels (various); blind; 
spitting-cup; formaldehyde generator (home-made). 
Bags: coke bag; moth bag; bags for cookery. 
PALISSY. ASA. PIONEER OF .SCIENTIFIG 
METHOD. 
EVERYONE is familiar with the dramatic story of 
Bernard Palissy, the potter, and how he fired 
a kiln with his household furniture in order to produce 
sufficient heat to melt his glazes, but his scientific 
work is rarely mentioned. A paper on ‘ Palissy, 
Bacon, and the Revival of Natural Science,’ by Sir T. 
Clifford Allbutt, published in the Proceedings of the 
British Academy (vol. vi.) is therefore a welcome con- 
tribution to the history of science. 
Palissy shares with Galileo and Gilbert the credit of 
being a pioneer ot modern scientific method. Born in 
1519, in Périgord, he was apprenticed to the art of 
glass painting, and in 1539 saw the cup of glazed 
faience which inspired him to produce a similar glaze 
upon ware. After he had succeeded, he found his way 
NOL 28330 VOUWwes| 
NATURE 
[JuLy 16, 1914 
to Paris, where he wrote books on many scientific sub- 
jects; and during the years 1575-84 he exercised great 
influence upon society in the city. He lectured on 
agriculture, chemistry, mineralogy, and geology, and 
illustrated his lectures with demonstrations of natural 
objects from his museum. “‘Into the faces of the 
learned of his time he thrust his facts; he urged the 
might of the verified fact, the tests of practical experi- 
ence, the demonstration of the senses; and these in a 
keen and original way.’’ Among the physicians who 
attended his lectures was no less a _ person than 
Ambrose: Pare. 
By observation and experiment Palissy combated the 
prevailing notion that springs originated in the perco- 
lation of sea-water into the earth; and he showed that 
they were formed at the junction of permeable and 
impermeable strata. He collected fossils widely and 
understood their nature; and both Buffon and Réaumur 
bore testimony to the correctness of his judgments 
upon this and other geological subjects. At the age of 
eighty Palissy was thrown into the Bastille as a dan- 
gerous heretic, and he died there after enduring about 
a year’s imprisonment. 
Sir Clifford Allbutt suggests that Francis Bacon, who 
went to Paris in 1576, and resided there for three years, 
must have been influenced by Palissy’s Museum or lec- 
tures, though. no mention of them is found in any 
existing work. ‘‘ What is certain is that Palissy was 
then teaching ‘practically the methods which a few 
years afterwards Bacon propounded at length; and 
not only so, but was teaching them, if with a far 
inferior literary capacity, yet with a sounder grasp of 
their methods.”’ ; 
Bacon constructed an imposing philosophical system 
of rules by which natural facts and phenomena were 
to be studied, but it was Palissy, Gilbert, and Galileo 
who were the real founders of the experimental method 
of inquiry upon which the superstructure of modern 
science has been built. 
EX PLOSIVES.+ 
AS explosive 1s a body which, under the influence 
of heat or shock, or both, is, speaking popularly, 
instantaneously resolved entirely, or almost so, into 
gases. 
Practical explosives consist either of bodies such as 
nitroglycerine and nitrocellulose, which are explosive 
in themselves, or mixtures of ingredients which 
separately are, or may be, non-explosive, but when 
intimately mixed are capable of being exploded. 
Explosives are exploded either by simple ignition, 
as in the case of black gunpowder, or by means of a 
detonator containing mercury fulminate. 
The molecules of an explosive may be regarded as 
in a state of unstable chemical equilibrium. A stable 
state of equilibrium is brought about by the sudden 
decomposition of the original compounds with the 
evolution of heat. An explosion is thus an extremely 
rapid decomposition, accompanied by the production of 
a large volume of gas and the development of much 
heat. 
There are two well-defined modes of explosion which 
can be described as combustion and detonation. In 
the former case, the explosive is simply ignited and 
combustion takes place by transference of heat from 
layer to layer of the explosive. The rapidity with 
which the combustion proceeds depends not only on 
the physical form of the explosive, but also on the 
pressure under which the decomposition takes place. 
‘When in the form of fine grains, combustion pro- 
+ From a course of lectures delivered before the Institute of Chemistry, at 
King's College, |London, by Mr. William Macnab, and published by the 
nstitute 
