628 
NATURE 
[OcTOBER 23, 1902 
and rapid growth of the science of bacteriology, and the 
special study of yeasts and fermentation has been 
dignified by the name of zymotechnology. By “ Protis- 
tenkunde” or protistology is denoted a wider field of 
study, embracing all Protista as its objects, and of 
which bacteriology and kindred sciences are but sub- 
ordinate branches. 
It is not surprising, therefore, that a journal has 
appeared which is to be devoted entirely to protistology. 
The Archiv fiir Protistenkunde will be welcomed by a 
wide circle of naturalists, and will find a place in every 
biological library. Edited by Dr. Fritz Schaudinn, who 
has himself pursued the study of Protozoa with such 
remarkable success, its high standard of excellence is 
practically guaranteed. The contents of the first number 
do not disappoint our expectations, while they show at the 
same time that the aim of the journal is to be scientific 
rather than practical. With contributions headed by 
names so well known as Hertwig, Biitschli, Brandt and 
others, the new journal makes a good start. 
The first article is contributed by Prof. R. Hertwig, 
and isa very interesting discussion on Protozoa in relation 
to the cell-theory. To show the scope of his dissertation, 
it must suffice to quote his principal conclusions. He 
attempts “‘to develop a uniform conception of the cell, 
applicable alike to Protozoa and Metazoa,” recognising 
that any such attempt does not rest at present on a very 
firm basis, but thinking it nevertheless more useful to 
formulate precise conclusions, which can be criticised, 
than to rest content with vague indications. 
‘““Three kinds of substances, characterised by the part they 
play in cell-life, must be assumed : (1) the achromatic sub- 
stance ; (2) the chromatin ; (3) the nucleolar substance. 
These three substances show the following distribution in 
the cell of the Metazoa, and probably also in that of multi- 
cellular plants. The protoplasmic framework—leaving 
out of consideration the material filling the meshes or 
alveoli (Biitschli)—represents an intimate union of achro- 
matic framework and chromatin, of which the latter is 
only separated out under special circumstances in small 
quantities, and then induces a heightened staining- | 
capacity of the cell body. . . . The linin-framework of the 
nucleus consists only of achromatic substance, in which is 
deposited the chromatin, bound up with nucleolar sub- 
stance and thereby organised. In this way arises the 
chromatic nuclear framework of authors. An_ excess of 
nucleolar substance forms the true nucleoli, which in the 
majority of cases are subsequently used up in the forma- 
tion of chromosomes in karyokinesis, in the Metazoa just 
as in Actinosphaerium.” 
The first number contains five other articles besides 
that of Hertwig, amongst which may be noticed one by 
Biitschli on the structure of the Cyanophycez and Bac- 
teriaceze, a monograph of the Coccolithophoride by 
Lohmann, and a discussion by Doflein of the outlines of 
classification of the Protozoa. 
divides the Protozoa into two main divisions: first the 
Plasmodroma, characterised by possessing organelles for 
locomotion 
“which can be easily recognised as protruded portions 
of the body-protoplasm, and which, moreover, in many 
cases can be extruded and withdrawn as required ” ; 
secondly the Ciliophora, in which the organs of loco- 
motion, when present, are cilia. The Plasmodroma com- 
prise the three classes Rhizopoda, Mastigophora and | 
NO. 1721, VOL. 66] 
The last-named author | 
Sporozoa; the Ciliophora comprise the Ciliata and 
Suctoria. 
In conclusion, it is only necessary to add that the 
various memoirs are illustrated, where necessary, by 
lithographed plates of the degree of excellence to which 
one is accustomed in German zoological periodicals. 
. E. A. M. 
AN ASSAVERS HANDBOOK. 
Assaying and Metallurgical Analysis for the use of 
Students, Chemists and Assayers. By E. L. Rhead 
and Prof. A. Humboldt Sexton, F.I.C., F.C.S. Pp.x + 
431. (London: Longmans, Green and Co.) Price 
Ios. 6d. net. 
ape differences between assaying and chemical 
analysis in the ordinary usage of the terms are 
perhaps not very precise. An effort was made some 
years back in America to apply the word “assaying” 
only to the estimation of some or all of the elements in a 
substance by means of dry reagents and heat, and the 
word “analysis” to all estimations by the use of reagents 
in aqueous solution. These definitions, however, have 
not met with much favour, and have little to recommend 
them. It would be better to limit “assaying” to the 
estimation of the valuable constituent or constituents of 
an ore or other substance, and to use ‘‘analysis” for the 
estimation of the other constituents and for all qualitative 
determinations. According to this view, a gold ore 
would be assayed for gold and silver, and the sulphur, 
copper, iron, &c., would be determined by analysis, 
while a copper ore would be assayed for copper, the 
sulphur in iron pyrites would be determined by assay, and 
so on. Messrs. Rhead and Sexton have in general 
followed this method, but there are difficulties in its 
adoption, and in any case an authoritative definition is 
required. 
There are already many books on the subject, and 
although some of them are out of date, the need of a 
new one which does not follow any strikingly original and 
advantageous plan does not seem pressing. It may be 
presumed that the authors of the book under review have 
found difficulties in teaching their students with the aid 
of the older books, and after supplying their own wants 
have decided to offer their system to other teachers. The 
result is by no means displeasing. The plan of the book 
is excellent. The student or assayer can find what he 
wants without delay, and the description of the required 
process is always terse, usually accurate and in many 
instances sufficiently complete. The accuracy, however, 
is unfortunately by no means without exception, but the 
chief fault of the book is that in the effort to reduce its 
size terseness has been pushed to an extreme, and the 
working directions are often insufficient to enable the 
process in course of description to be properly carried 
out even by an assayer of some experience unless he has 
been previously taught what to do. 
An example of the lack of accuracy occurs in the 
description of the iodide method of estimating copper, in 
the course of which on p. 79 the student is informed that 
“ Cupric salts liberate iodine from potassium iodide. 
The liberated iodine may be estimated by means of a 
solution: of potassium thiosulphate of known strength, 
sodium iodide and sodium tetrathionate being produced.” 
