vi PEEFACE 



portion of which have been used for laboratory demonstration in 

 the class room. The magnification in each case is precisely stated. 



The original drawings, of which there are about one hundred, 

 have been prepared by the author with the aid of the camera lucida. 

 The photomicrographs, of which one hundred and twenty-two are 

 original, were made, under the author's direction, by Mr. J. N. Lett, 

 and a few by Mr. F. E. Ives. My thanks are due these gentlemen 

 for their able assistance. The illustrations in color have also been 

 drawn by the author with the aid of the camera lucida, and have 

 been reproduced by a process specially devised for the purpose. 



. I desire at this time to acknowledge my indebtedness for numer- 

 ous illustrations which have been reproduced from the literature. 

 The author's name has in each case been appended to the legends 

 of these figures, and a reference to the bibliography will serve as a 

 more precise acknowledgment of their source. 



The list of literature has been arranged in accordance with 

 the main subdivisions of the text, to facilitate ready reference to 

 special topics, and in the hope that the earnest student maybe 

 tempted to search beyond the confines of the text-book, and thus 

 acquire a broader appreciation of the subject. To much of the 

 recorded literature the author has been frequently indebted during 

 his experience as a teacher, and it is a pleasure to be able to grate- 

 fully acknowledge his indebtedness to these sources. 



A limited chapter on technique has been inserted at the end. 

 The limits of the work do not permit an extended treatise on this 

 subject, a science by itself, but it is hoped that the few fundamental 

 facts which have been briefly stated may serve to give the student 

 a more exact idea of the methods by which tissues are prepared for 

 examination, and the means by which the more important results 

 have been obtained. 



Finally, it is a pleasure to acknowledge the repeated courtesies 

 which have been frequently received at the hands of the publishers. 



JEREMIAH S. FERGUSON. 

 NEW YORK. 



