8 PREFACE 



ment of knowledge by means of morphological studies have become 

 reduced to a minimum, while the fields of pathological physiology 

 and chemistry lie still almost unexplored. The development of 

 research upon the subject of natural and acquired immunity has 

 presented innumerable problems, all of which are essentially chem- 

 ical. And perhaps most important of all is the general awakening 

 of an appreciation of the importance of physiological chemistry to 

 medical science, which has led to the introduction of laboratory 

 courses on this subject in every medical school worthy of the name. 



A book on Chemical Pathology should, therefore, seek to supply 

 information to a varied group of readers. It should furnish col- 

 lateral reading to the student who for the first time goes over the 

 subject of General Pathology, which his text-books usually consider 

 chiefly from the morphological standpoint. It should exploit to the 

 graduate in medicine the advances that are being made along lines 

 that are of fundamental importance to clinical medicine. It should 

 serve for the investigator in biological chemistry or in pathology as 

 a source of information concerning the ground upon which the two 

 subjects overlap the " Grenzgebiete " of Pathology and Physio- 

 logical Chemistry. And, above all, it should afford a guide to the 

 sources of our knowledge of these subjects, since nothing but direct 

 familiarity with the original reports of the investigators themselves 

 can give the student an impersonal view of the actual status of the 

 questions under consideration. On account of this multiplicity of 

 the objects in view, it has often been necessary to consider certain 

 topics from more than one standpoint ; which explains, perhaps, 

 certain apparent irregularities in the style and manner of treatment. 



It has been assumed that the reader has at least an elementary 

 knowledge of organic and physiological chemistry. For the benefit 

 of those whose studies in these subjects date back some years, it has 

 seemed advisable to include in an introductory chapter an epitome 

 of the more modern views concerning the chemistry of the proteid 

 molecule, the composition of the animal cell, and the principles of 

 physical chemistry, in as far as they apply to biological problems. 

 The general consideration of " Enzymes " in Chapter II is written 

 with a similar object. In discussing these fundamental topics it has 

 seemed advisable to omit detailed references to the numerous origi- 

 nal sources, these may be found quoted in the special text-books 

 cited in the foot-notes ; but in presenting the more distinctly patho- 

 logical topics the attempt has been made to render all the important 



