May 12, 1911] 



SCIENCE 



745 



the globose, thick-walled chlamydospores belonging 

 to a Fusarium. 



In a discussion following the Jones and 

 Lutman paper at the American Association 

 for the Advancement of Science meeting at 

 Boston last year, Giissow said that he had seen 

 these slides, and that the oospores much re- 

 sembled the bodies that Jones and Lutman 

 had obtained in their artificial cultures. The 

 writer has not seen these slides, though he 

 tried to obtain examples of the oospores from 

 Smith a few years ago. Smith wrote at that 

 time: 



No doubt you know that the oospores became a 

 kind of political subject — oospores of P. infestans 

 or not oospores of P. infestans? — and I had no 

 wish to go on. Botanists and popular writers fol- 

 lowed what they took to be the safer authority, 

 just as Saccardo has done; this is right enough in 

 a way. 



While we have not seen these slides, on 

 every possible occasion during the eight years 

 that we have been studying this fungus, we 

 have looked for oospores in the leaves and 

 tubers under the conditions described by Smith. 

 While we have never found spores that satis- 

 fied us that they were the potato blight 

 oospores, we have found oospore-like bodies, 

 both of animal and fungous origin, that might 

 be mistaken for such, and possibly might be 

 some of those bodies described by Smith. 

 We have seen Smith's drawings, and his 

 photomicrographs published in the Quarterly 

 Journal of Microscopical Science, Vol. 15, in 

 1875, and the drawings of Montague, pub- 

 lished by Berkeley in the Journal of the 

 Horticultural Society, Volume 1, in 1846, 

 these latter being considered by Smith to 

 represent the same thing he described as the 

 oospores. None of these impress us as being 

 the same as the true oospores that we have 

 obtained in cultures. The only figures that 

 at all show a resemblance are Figs. 134 to 136 

 in Smith's book on " Diseases of Field and 

 Garden Crops," published in 1884. We are in- 

 clined to believe that these botanists had a 

 variety of things under consideration, and 

 while it is quite doubtful if any of them 

 were the oospores of potato blight, we do not 



wish to make a positive assertion without see- 

 ing the original preparations. 



In 1904 we first began to study the potato 

 blight in artificial cultures. So far as we 

 know, we were the first to make such cultures 

 in this country, or at least to publish notes on 

 them,* but in looking up the literature at the 

 time, it was found that two French botanists, 

 Matruchot and Molliard, had secured cultures 

 even earlier. Their results, published in 1900 

 and 1903, were similar to those we had ob- 

 tained; viz., the fungus was grown in certain 

 media with fair success, but no oospores ap- 

 peared, though we did very rarely find curious- 

 shaped threads that might indicate futile at- 

 tempts to form oogonia. 



At the Baltimore meeting of the American 

 Association for the Advancement of Science, 

 in December, 1908, Jones and Giddings gave 

 a paper' in which they described these curi- 

 ously shaped threads which had appeared with 

 more or less frequency in stab cultures of a 

 specially prepared potato-gelatin medium that 

 they used. Jones was inclined to believe that 

 they were attempts at oogonial formation, 

 though there were no indications of antheridia 

 or oospores. At the same meeting the writer^ 

 described a special medium, Lima bean juice 

 agar, on which the potato blight grew with 

 far greater vigor than on any medium yet 

 tried, so that its continued cultivation was as 

 easy as that of any parasitic fungus. On this 

 medium, however, no oospores appeared, and 

 very rarely even the curious-shaped threads, 

 though when Phytophthora Phaseoli, a near 

 relative, was grown on it, oospores appeared 

 in profusion. 



At the Boston meeting of the American 

 Association for the Advancement of Science, 

 Jones and Lutman gave a second paper'' in 

 which they further discussed these curious 

 bodies that appeared in their cultures. Though 

 not stating positively that these bodies were 

 of the nature of oogonia, they were inclined to 

 consider them as resting spores. While much 



'Conn. Agr. Expt. Sta. Eept., 1905. 

 - Science, XXIX., 271, February 12, 1909. 

 »Conn. Agr. Bxpt. Sta. Eept., 898, 1908. 

 * Science, XXX., 813, December 3, 1909. 



