310 BOTANICAL GAZETTE [APRIL 
the use of students with no previous knowledge of chemistry. The first 154 
pages are devoted to elementary chemistry. The headings of the remain- 
ing chapters will indicate the scope of the rest of the book. These are: 
the water-content and ash of plants; the non-nitrogenous organic com- 
pounds of plants; the nitrogenous organic compounds of plants; the chem- 
istry of plant growth; composition of plants at different stages of growth ; 
factors which influence the composition and feeding value of crops; compo- 
sition of coarse fodders: wheat; maize; oats, etc.; mill- and by-products; 
roots, tubers, and fruits; fermentation ; chemistry of digestion and nutrition ; 
rational feeding of animals; composition of animal bodies; rational feeding 
of men. Interspersed throughout the book are directions for numerous 
simple experiments, designed to be performed by the pupil. 
The chapters on pure chemistry deal only with the most important elements 
and compounds which enter into the composition of plants and animals, 
The treatment, in this part of the book, is very elementary, and often decid- 
edly dogmatic. Some statements occur which are not free from serious 
objection. Thus on page 3: ‘It was believed, at one time, that metals, as Cop- 
per, could be changed into gold, and other substances into different forms of 
matter. After many centuries of experimenting it was found that this could 
not be done, and as a result the law of the indestructibility of matter was 
established.” The “change of substances into different forms of matter” is 
one of the principal subjects of the chemist’s study. On the other hand, the 
question of transmutation has no bearing on the doctrine of the conservation 
of matter, On page 4 we find: “The reasons for accepting the molecular 
Structure of matter cannot be profitably taken up by the student of elemen- 
tary chemistry.” Andon page 13: “The way in which atomic weights are 
obtained cannot at this stage of the work, be profitably considered.” ‘The 
subject is not considered later; but, nevertheless, the terms “atom” and 
“molecule ” are constantly employed, as are also chemical formulas, which 
are introduced on the twelfth page. It is to be feared that the student will 
gain the idea that atomic weights and formulas are obtained in some mysteri- 
ous way, and that the properties of substances are to be deduced from these data 
by some sort of algebraic manipulation. Thus on page 73 it is stated: “ In 
the study of acids, bases, and salts the character of the compound can always 
be determined from the formula, as Ca(OH)...” The treatment of valence 
is equally objectionable. Under the heading “ Impossible reactions,” page 
123, itis stated that in “ the case of BaSO,-+2HCI no reaction can take 
place,” because these substances are the products of the action of BaCl; ~~ 
H;SO0,. This would seem to teach the impossibility of reversible reactions. 
Some Statements are inaccurate. Thus, page 24: ‘Liquids are never 
weighed, but always measured ;” page 40, “ Hydrogen is liquefied with 
greater difficulty than any other element.” This ignores helium. On page 
58, speaking of water of Crystallization, it is said: “ Without this water crys- 
tals could not be formed.” On page 113, benzene (C,H,) is referred to as 
