to 
i) 
NAT ORE 
[ DeceMBER 10, 1896 
troversial matter. Rules for experimental and_intro- 
spective research and illustrations of their application 
are arranged and expounded in a thoroughly methodical 
manner. The author admits only two ultimate kinds 
of “conscious elements”—sensation and affection— 
definitely rejecting actzvzty as a third conscious element. 
Space is devoted to what may be called ‘“ Numeral 
Psychology,” ze. the estimate of the total number of 
different conscious elements. The method, of course, is 
to ascertain the just discriminable difference. Underlying 
this whole procedure there appears to be a logical fallacy, 
or at least a difficulty which modern text-books entirely 
ignore. Thus, suppose that a, 6, c, d,e,f.. . is a series 
of measurably different physical stimuli, and A, B, C, 
D, E, F ... the sensation-processes supposed to cor- 
respond with the stimuli. Suppose, further, that a—d or 
A—D represents the just discernible difference. Then, 
by hypothesis, sensation A zs just distinguishable from 
sensation D, while sensation B is vo¢ just distinguishable 
from sensation D. Hence sensations A and B have 
opposite predicates, and therefore they are different, 
although, by hypothesis, they are consciously un- 
distinguishable. Now in “counting” the number of 
sensation-elements, it is always assumed that difference 
means the same as distinguishableness. But that this 
leads to logical contradiction is obvious from the above, 
while it is in flat opposition to Weber's logarithmic 
formula, which implies that a continuous variation 
of stimuli corresponds to a continwous—-not discrete— 
variation of sensation. The author's mode of dis- 
tinguishing (1) sensation, whether peripherally or 
centrally aroused, (2) perception or idea, and (3) the 
association of ideas, seems decidedly original and worthy 
of careful consideration. No doubt he is right in making 
the distinction between (1) and (2) depend on the absence 
or presence of objective significance ; but it seems un- 
satisfactory to offer only a “biological reason” (p. 183) 
for the unity possessed by the perceptual or ideal complex 
of sensations. Again, in treating of conception, judg- 
ment and reasoning, no higher mode of intellection 
seems to be recognised than association. We feel our- 
selves carried back to the dark ages of psychology when 
we read (p. 301)— 
“We speak of a comparison of two impressions when 
the ideas which they arouse in consciousness call up the 
verbal associate ‘alike’ or ‘different’ ... We have in 
this process of comparison or discrimination, then, a case 
of verbal association.” 
We are curious to know whether the words “alike” 
or “ different * have any significance ; and, if so, whether 
this significance is an object of conscious apprehension 
or not. Other passages point to similar defects, owing 
to the author’s confidence in sensation and association 
as the sufficient materials for all intellectual processes. 
It is true that the author avoids many of the fallacies of 
the old mechanical view of association, and many parts 
of his exposition are unexceptionable in the light of 
modern criticism, But the characteristics of the book 
that are to be most highly commended are clearness, 
simplicity, wealth of illustration, and, in general, adapt- 
ation to the needs of the beginner who requires to be 
placed ex rapport with the latest results of experimental 
psychology. W. E. JOHNSON. 
NU. 1415, VOL. 55] 
A MANUAL OF DAIRY WORK. 
The Book of the Dairy. Translated from the German 
of W. Fleischmann by C. M. Aikman and R. P. 
Wright. Pp. xxiv + 344. (London: Blackie and 
Son, 1896.) 
O branch of practical agriculture has made greater 
progress during the last quarter of a century than 
that which may be broadly described as dairy farming. 
The evidences of this advance are to be sought, however, 
not so much in the operations antecedent to the pro- 
duction of milk as in the processes employed in its after 
treatment. In making this assertion, we do not overlook 
the improvements which dairy farmers have effected in 
the housing, feeding, and general management of milch 
kine. But these have resulted mainly from the intelligent 
modification of time-worn practices. whereas in the 
manipulation of milk, either for sale as such, or for 
manufacture into butter or cheese, there has been ample 
scope for modern ingenuity in the introduction of novel 
methods. The cow remains to-day what she has been 
for ages—a physiological implement for the production 
of milk, and we may recall the words of Charles Dickens, 
“Tf civilised people were ever to lapse into the worship 
of animals, the Cow would certainly be their chief god- 
dess.” Cows, especially of certain breeds, have, by 
judicious selection exercised by the breeder, been greatly 
improved in their milk-yielding capacity, in respect both 
of quantity and of quality. But there is no essential 
distinction between the cows of to-day and those which 
furnished milk to our Saxon ancestors—the difference is 
only one of degree. On the other hand, the change 
in the methods and appliances of the dairying industry, 
even if the comparison be made with so recent a period 
as only thirty years ago, is so profound that it may well 
be termed revolutionary. The displacement of the old 
system of cream-raising by the rapid work of the centri- 
fugal separator, the rational use of micro-organisms in 
the ripening of cheese, the sterilisation of milk in the 
destruction of tuberculous and other germs, the direct 
and almost instantaneous manufacture of butter from 
fresh milk, are only a few illustrations of what has been. 
accomplished in very recent years. With such changes 
constantly in progress an extensive literature has sprung 
up around the industry of dairying, and many notable. 
works upon the subject have been published in the 
English, French, German, and Danish languages. 
Of the dairying experts of Germany, no one occupies a 
higher position than Dr. Fleischmann, of Koénigsberg, 
and no doubt many readers will welcome an English. 
translation of his well-known manual of the science and 
practice of dairy work, which Messrs. Blackie have 
issued in a style deserving of commendation. The first 
chapter deals with the secretion, properties, and com- 
position of milk, and discusses the defects which give 
rise to bitter, coloured, ropy, lazy, or sandy milk. The 
extraction, immediate sale, and testing of milk form the 
subject of the next chapter, which is partly commercial 
in its scope. For the third chapter the translators have 
chosen the not very intelligible title of “Milk in its 
relation to micro-organisms, dairying, and bacteriology.” 
Butter-making and cheese-making are the respective 
subjects of the two succeeding chapters, which are 
