8 
der Autoxydation,” by C. Engler and J. Weissberg (Braunschweig, 
1904). I am especially indebted for much valuable information to 
a dissertation by Pierre See, entitled “Contribution a l’Etude des 
Applications Therapeutiques des Oxydases et des Metaux Ferments” 
(These, No. 239, Faculte de Medicine de Paris, 1905), and to recent 
articles by Engler and Herzog, “Zur chemischen Erkenntnis bio- 
logischer Oxydationsreaktionen” (Hoppe-Seyler’s Zeitschrift fur 
physiologische Chemie, 1909, vol. 29, pp. 327-375), and to Moore and 
Whitley, “The properties and classification of the oxidizing enzymes 
and analogies between enzymic activity and the effects of immune 
bodies and complements” (Bio-Chemical Journal, 1909, vol. 4, pp. 
136-167). In many instances in dealing with original contributions 
to the subject I have adhered as closely as possible to the words of 
the author in order that the exact sense and meaning of the original 
article might be preserved to at least as great an extent as possible 
within the limits of the present communication. Furthermore, no 
claim is made for the completeness of this production. It has been 
impossible, through lack of time and space, to refer to all original 
communications on the subject, even in the bibliography. Even 
the current numbers of the journals contain many contributions 
bearing on the subjects treated of in the following pages, and out of 
this vast and constantly growing literature I have been compelled to 
select what seemed to me the most essential to the proper presentation 
of the subject. 
In the writer’s opinion the subjects considered in the following 
pages are strictly germane in their general scope to the work of the 
Hygienic Laboratory. The oxidases and related oxygen-catalysts 
belong to the same group of bodies as the serums, viruses, toxins, 
and antitoxins. Any facts throwing light on the one class of sub- 
stances will doubtless assist ultimately to a better understanding of 
this whole group of biologically active substances. Portier is of the 
opinion that the oxidases play an important role in the defense of 
the organism against pathogenic micro-organisms, and according to 
Sieber they are able to destroy toxins, such as the toxins of diphtheria 
and tetanus. Furthermore, they are of importance as enabling us to 
form 'correct conclusions regarding the condition and character of 
certain foodstuffs — as to whether they are cooked or raw — and in 
enabling us to determine, within certain limits of temperature, 
whether a given sample of milk has been pasteurized or not. For j 
the biological chemist, the physician, and the sanitarian, all of these 
matters are of considerable importance. 
I am greatly indebted for much valuable material to various 
authors, whose works I have freely consulted and made use of in the 
preparation of this monograph, and also to Mr. F. A. McDermott, 
one of the assistants in the division of chemistry of the Hygienic . 
Laboratory, for much valuable assistance. 
