348 



SCIENCE 



[N. S. Vol. XXVI. No. 663 



■witli Bordeaux mixture will prevent the dis- 

 ease, either acting directly or indirectly. He 

 states that the ginseng fungus is a wound 

 parasite, but, so far as I can see from any 

 facts advanced, this is only an assumption 

 which may or may not be true. I should like 

 to know whether this is entirely a post hoc 

 conclusion or something which was actually 

 demonstrated, and if so, how demonstrated, 

 and why he has not published his proofs ? He 

 nowhere says that he actually found the Fu- 

 sarium entering the plant through wounds in 

 the stem caused by the anthracnose, although 

 this, from the standpoint of his hypothesis, 

 was one of the first things to look for and to 

 be made out conclusively, not inferentially, 

 especially if he proposed to use it as a basis 

 for criticism. 



To come now to those things which relate 

 specially to my ovm work and are manifestly 

 unwarranted inferences : 



1. How does he know that the organism he 

 worked with belongs to the genus Neocos- 

 mospora? He states distinctly that he did not 

 find any peritheeia. We know that not all 

 members of the form-genus Fusarium belong 

 to Neocosmospora, and also that inspection of 

 the imperfect stages does not suffice to tell. 

 This then is an uncertain inference put for- 

 ward as a fact. 



2. How does he know that his identification 

 of the g\ni,eng-Fiisarium with the watermelon- 

 fungus is correct? I doubt it. He did not 

 make any comparative study of the two fungi, 

 although it would have been easy for him to 

 obtain the melon-fungus, since the disease is 

 widespread in the southern United States, and 

 probably occurs in Missouri, possibly in some 

 of the soils he worked with. Why did he not 

 make comparison between the two organisms 

 rather than between his organism and my 

 description? 



3. How does he know from his very limited 

 experiments with one species that all Fusaria, 

 and the Neocosmosporas in particular, are 

 weak parasites? He states that he found the 

 ginseng fungus to be a weak parasite, but I 

 have just pointed out that even this is not 

 established conclusively from his papers. 



How, then, can the much larger inference be 

 sustained? One can not reach general con- 

 clusions from a single particular. It does not 

 need any very extensive course in logic to 

 convince one of this. 



4. How can inferences of any value re- 

 specting this group of fungi be based on 

 such a sandy foundation? From his state- 

 ments the reader is led to think that the 

 watermelon fungus must be a weak parasite 

 and that the plant must first be attacked by 

 Thielavia hasicola or some other fungus before 

 the Fusarium can possibly find an entrance 

 into it, although Dr. Eeed probably never saw 

 the melon-fungus, and has not proved that the 

 ginseng-fungus can not enter the plant in the 

 absence of wounds. 



When this paper of Dr. Reed's first came 

 out, I was in Europe, but my colleague, Mr. 

 Orton, obtained cultures of the ginseng- 

 fungus from Dr. Eeed and carefully compared 

 it on various culture media with the water- 

 melon-fungus which we had in culture in the 

 laboratory, and found that they behaved differ- 

 ently and were probably not identical organ- 

 isms. This is the sort of work Dr. Eeed 

 ought to have done and not left for some one 

 else to do. 



Mr. Orton also made in one of our hothouses 

 the following three sets of inoculation experi- 

 ments, using autoclaved soil: 



1. Watermelon-plants ; the soil inoculated 

 with the gmseng-Fiisarium, obtained from Dr. 

 Eeed. Ten inoculated pots and ten control 

 pots. 



2. Watermelon-plants; the soil inoculated 

 with the cotton-Fusariam. Ten inoculated 

 pots and ten control pots. 



3. Watermelon-plants ; the soil inoculated 

 with the watermelon-Fusarium. Ten inocu- 

 lated pots and ten control pots. 



The results were as follows : 



1. No cases of melon-wilt in the pots in- 

 oculated with the ginseng-organism. (Experi- 

 ment agrees with Dr. Eeed's corresponding ex- 

 periment.) 



2. No cases of melon-wilt in the pots in- 

 oculated with the cotton-organism. (Experi- 



