8 PREFACE 



presence or absence of a diacritical mark, I have not abbreviated owing to 

 ease with vt^hich diacritical marks are overlooked in proofreading. The num- 

 ber of the series has been given in Roman numerals, the volume number in 

 boldface, and where the pagination is not continuous, the number of the 

 article or part is given in ordinary type between colons. 



Some care has been taken to ascertain the dates of publications where 

 new species or new combinations are proposed, since this date is the effective 

 one for deciding questions of priority. If it is desirable to record the first 

 isolation of an organism as a matter of historical interest, it should not be 

 connected with the scientific name in bibliographical citations. From bitter 

 experience one learns to disregard the dates given by certain authors, or to 

 add from one to ten years to the dates given. When an author indulges in 

 this practice with reference to his own new species and uses the date of publica- 

 tion or even misquotes the latter in the case of species proposed by others, 

 one cannot help but suspect intentional dishonesty. 



Another objectionable practice of some authors is the copying of a bibli- 

 ography without verifying the citation or reading the article quoted. For 

 example, many authors quote Bohin 1847 when they really mean Bohin 1853. 

 In Robin's doctoral thesis, Les vegetaux qui croissent sur les animaux vivants, 

 viii, 120 pp., 3 pis., Paris, 1847, he uses only the name Achorion Schoenleini, 

 although he summarizes the work of previous authors very carefully. "When 

 the thesis was reissued in book form under the title Histoire naturelle des 

 vegetaux parasites qui croissent sur I'homme et sur les animaux vivants, x, 704 

 pp., Paris, 1853, with an Atlas of 15 plates, the text was greatly expanded and 

 the various organisms were given scientific names. Hence all names attributed 

 to Robin should be cited 1853 not 1847. It follows that when an author cites 

 Robin 1847 for a species name, he is copying without having read the very 

 rare thesis of that date. Such carelessness tends to throw doubt upon an 

 otherwise acceptable piece of work. 



It is recognized that errors occur in proofreading, but it is felt that by 

 giving complete bibliographic data as to volume and year, there is little 

 chance that both will show the same typographic errors. The author will 

 be grateful for corrections of errors, for information of the location of refer- 

 ences marked with an asterisk or for references to significant work which 

 has been overlooked or to new literature, looking toward a revision. 



The chapter on microscopy and staining has been kindly contributed by 

 Dr. Morris Moore and the section on hydrogen ions (pp. 34-38) by my wife. 

 The text-figures have been redrawn from original sources, duly acknowledged 

 in each, by Dr. Gladys Baker, Mr. Albert Heinz, Dr. Morris Moore and the 

 late Mr. Thomas O'Brien, most of those except the yeasts by the latter. The 

 drawings by Dr. Morris Moore are the result of his own research. 



While the author assumes full responsibility for the statements of this 

 book, he is grateful to Dr. Margaret B. Church of Urbana University, to Dr. 

 Morris Moore of the Barnard Free Skin and Cancer Hospital of St. Louis, 

 and to Dr. Joseph Swartz of the Medical School of Harvard University for 



