490 



Connecticut State Station, Bulletin No. 105, December, 1890 (pp. 8). 



The potato scae, li. Thaxter, Ph. D. (pp. 3, 4). — As the result of 

 several months iuvestigatiou of potato scab at the station, it is an- 

 nounced that the disease is due " to the direct action of a very peculiar 

 filamentous fuugus of extremely small dimei>sious, which has been 

 found invariably to accompany the disease wherever it has been exam- 

 ined by the writer in New England." 



This fungus produces an evanescent gray film in connection with the disease, geu- 

 erally visible without a lens, especially in the earlier stages of the affection, and has 

 been obtained absolutely pure for experiment by the ordinary methods of isolation 

 used in bacteriology. On nearly all neutral or slightly acid substrata used for its 

 cultivation, it forms a compact lichenoid growth accompanied by a peculiar dark 

 stain whit;h diffuses from it through the nutrient substance. Its fructification is 

 aerial and consists in the production of short, rod-like bodies and spirals; the latter 

 terminal, the former resulting from the general segmentation and breaking up of the 

 aerial filaments into short pieces; the general mass, which is bluish-gray in color, 

 closely resembling various forms of bacteria in shape and size ; the diameter of both 

 the vegetative and reproductive portions of the plant reaching only from five to eight 

 ten-thousandths of a millimeter on the average. The fungus, which, except for its 

 apparently true-branching and aerial fructification, resembles in some respects cer- 

 tain of the polymorphic bacteria, can not as yet be referred to any described form and 

 answers to no generic description, as far as has been ascertained. It is readily pro- 

 pagated by means of its spores as well as by the smallest possible portions which can 

 be detached from its vegetative filaments. When transferred from pure cultures to 

 young, growing potato tubers, it reproduces the disease upon them with certainty at 

 the point of application, under rigid experimental conditions. * * » 'Whether 

 the disease under consideration is identical with that which, as previously men- 

 tioned, has been referred to a bacterial origin is quite another matter", and there is 

 every reason to believe that the two are wholly distinct affections except iu so far 

 as their results are somewhat similar. Further than this nothing can be said, except 

 that the disease here investigated usually takes the form of what has been called 

 "deep" scab, which may possibly be found to be distinct in origin from the "sur- 

 face" scab with which it is often associated even in New England. 



In connection with this subject a study is being made of another organism mor- 

 phologically identical with the scab fungus, but apparently somewhat difterent 

 physiologically. This organism, which maj' nevertheless ultimately prove to be en- 

 tirely identical with the scab fungus, is one of the commonest forms of growth upon 

 rubbish, old hay or straw, barn-yard manure, and similar substances, and its study 

 is being prosecuted with a view to ascertain whether this identity, if it can be shown 

 to exist, may not furnish a rational explanation of the observed fact that land con- 

 taining much miscellaneous rubbish or fertilized with barn-yard manure is generally 

 associated with scab in the potatoes raised upon it. 



The PROTEiDS or albuminoids of the oat kernel, T. B. Os- 

 borne, Ph. D. (pp. 5-7). — A statement of the results of an extended 

 study of these materials, a brief summary of which was recently given 

 in Experiment Station Record, Vol. II, p. 304, The details of this in- 

 vestigation are to be printed in the Annual Report of the station for 

 1890. 



