250 



SCIENCE 



[N. S. Vol. LII. No. 1341 



are fairly well isolated. With the exception of 

 one neighboring place, located about 400 yards 

 from the Hill buildings, all other neighbors 

 are at least a half mile distant. The cinna- 

 mon rats had not been observed prior to last 

 Christmas, when Miss Hill saw a single ani- 

 mal in the grain house. From time to time 

 others were seen in increasing numbers about 

 the place. 



The rats in the farm buildings have reached 

 such numbers that they have become very de- 

 structive. This coupled with the fact that 

 bubonic plague has appeared in Texas, made 

 it necessary to attempt their extermination. 

 During the past few weeks over 1,000 rats 

 have been killed, and among these were found 

 a number of the cinnamon variety. From the 

 best available data, I estimate that at present 

 the proportion of cinnamon specimens to all 

 others is about 15 to 200. 



The cinnamon rat has not been observed at 

 any of the neighboring places, with the excep- 

 tion of the one located 400 yards away, where 

 two animals were recently seen. All of the 

 evidence points to the conclusion that this new 

 variety arose, possibly as a mutation from 

 Mus alexandrinus, on the Hill farm some time 

 during the latter part of last year. 



This rat should furnish an opportunity for 

 some interesting genetic studies. In a recent 

 letter Professor Castle has called attention to 

 the value of this material. He says: 



This would be very interesting genetic material 

 for there is known to be a yellow variety of the 

 roof rat, in addition to the black variety {Mus 

 rattus), and if this cinnaimon variety can be added 

 to the number (with albinism, which I presume 

 must exist among roof rats), it would be possible 

 to work out from this material a parallel series to 

 that which occurs in the Norway rat, possibly 

 even a more complex series, and it would be of 

 interest to know whether the linkage relations are 

 the same in the two species. 



J. T. Patterson 



Austin, Texas, 

 July 22, 1920 



ANOTHER CORN SEED PARASITE 



A FUNGUS which seems to have had very 

 little consideration as a parasite has recently 



been isolated from sweet corn seed by the 

 writers while making a study of the internal 

 parasites of some agricultural seeds. 



This fungus was frequently found in corn 

 from a field that last year had many dwarf 

 and distorted stalks and some barren stalks 

 and root rot. Seeds of this corn were ex- 

 amined for internal parasites by treating 

 three minutes with corosive sublimate solu- 

 tion according to a method which the authors 

 have worked out and found to be very satis- 

 factory. After this external disinfection they 

 were planted in sterile tubes of nutrient solu- 

 tion on cotton. In about a week a white 

 fungTis had grown out from many of the seeds, 

 some of which had also germinated. The 

 roots of the seedlings were attacked by the 

 fungus and died in about two weeks. Healthy 

 seedlings in sterile tubes were inoculated and 

 died in five to nine days. 



The pathogenicity of the fungus was ivx- 

 ther tested under more normal conditions on 

 corn grown in pots in the greenhouse, by 

 poiu-ing a suspension of the spores from pure 

 cultures around the roots and by punctures 

 with an infected needle just above the gTound. 

 Several of the plants so infected showed the 

 dwarfness and distortion seen in the field the 

 previous year. Those inoculated by puncture 

 made 19 per cent, less growth in height than 

 the controls and the soil inoculations made 13 

 per cent. less. Fungous mycelium was found 

 in the discolored tissue at the base of the stem 

 of these infected plants and the original 

 fungus was obtained in cultures from this 

 diseased tissue. 



This fungus corresponds very well, so far 

 as one of its methods of spore formation is 

 concerned, with descriptions and figures of 

 Oospora veriicilloides Sacc, found on com in 

 Italy by Saccardo in 1877. It was extensively 

 studied by Tiraboschi^ in an investigation of 

 organisms in com that might be connected 

 with pellagra. Tiraboschi, like practically all 

 other students of corn diseases, apparently 

 overlooked similar work done in Eussia in 

 1805 and 1896 by Deckenbach, who in addi- 



1 Annali di Botanici, 1905. 



