August 17, 1906.] 



SCIENCE. 



217 



other pre-Darwinian writers, this is a display- 

 either of mental density or of something 

 worse, for he understood quite well what I 

 meant, as is seen by his own use of the word 

 ' always ' further on-^^ 



My two main contentions are: that de 

 Vries's conception of elementary species is 

 inadequate^ and that elementary species ireed 

 true, not hecau-se they are the product of a 

 peculiar Jcind of variation, called m,utation, 

 l)ut 'because they have been subject to the 

 processes of selection and separation. These 

 essential points in my criticism have been 

 overlooked by Gager, and he is content to say, 

 with regard to the first one, that nobody, ex- 

 cept makers of dictionaries, knows what a 

 species is. With regard to my second conten- 

 tion, he fails entirely to see that it is inti- 

 mately connected with the first one, and has 

 made no attempt to demonstrate that muta- 

 tion is capable of producing true breeds with- 

 out the help of selection and segregation, and 

 that the latter two factors do not play an 

 essential part in de Vries's experiments. For 

 the rest, he only points to de Vries's defini- 

 tions of terms, which I reject; he points to 

 the facts represented by the experiments, 

 which I accept, but consider unsatisfactory 

 and incomplete; and he points to the value of 

 the experimental method as the only one that 

 is apt to decide questions of evolution, which 

 I positively deny. Experiments are valuable, 

 but they should be properly understood, and 

 should be correctly explained. The interpre- 

 tation of his experiments given by de Vries 

 is faulty, although the experiments themselves 

 are indisputable facts; and the fallacy is due 

 to his ignorance of the fundamental laws of 

 evolution, and to his incorrect conception of 

 the term species: with the latter his theory 

 stands and falls." 



I hope that this will be sufficient, even to 

 Gager, to define my standpoint, and, if any 

 further discussion should be considered neces- 

 sary, that it will take up the essential points 

 of my views, and not merely repeat the argu- 



"I/. c, p. 88, foot-note 65: 'Since the process 

 has been recognized and described.' 

 ^° Science, June 22, 1906, p. 948. 



ments of de Vries. Gager has done only this, 

 in a way which clearly lacks understanding of 

 what I really object to. If he further would 

 consider the rule, not to throw stones at people 

 out of a glass house, and observe the necessary 

 fairness to others, this would make the discus- 

 sion a more pleasant and profitable one. 



A. E. Ortmann. 



Carnegie Museum, Pittsburg, 

 July 23, 1906. 



SPECIAL ARTICLES. 



HERBARIUM TYPE SPECIMENS IN PLANT 



MORPHOLOGY. 



The close relationship existing between the 

 different branches of botany and the de- 

 pendence of these various branches upon each 

 other make it very important that every pre- 

 caution should be taken by the workers of 

 each branch to make their specialty as help- 

 ful as possible to all other divisions of the 

 subject. With the advancement of each phase 

 of the subject the points of relationship be- 

 come more prominent and the necessity for 

 the preservation of records, specimens, etc., 

 becomes of greater and greater importance. 



Between no two branches of botany is the 

 necessity of coojjeration greater than between 

 taxonomy and morphology. The taxonomist has 

 long recognized the importance of type speci- 

 mens and large herbaria have been brought 

 together and maintained at great expense 

 where these types may be preserved and 

 studied to the best advantage. The morphol- 

 ogist has probably in most cases preserved his 

 microscopic specimens, but in how many cases 

 has the morphologist prepared herbarium 

 specimens of the species on which he is work- 

 ing? This custom may and probably is fol- 

 lowed by many workers, but it is also true that 

 many morphologists have not only neglected 

 to preserve type material but in many in- 

 stances have not even taken the precaution to 

 have their determinations verified by special- 

 ists in taxonomy. 



If morphological botany is to add anything 

 to our knowledge of taxonomic botany, it ap- 

 pears to the writer that herbarium specimens 

 should be carefully prepared, properly labeled. 



