MISCELLANY. 



125 



The Potato-Disease.— It 13 quite certain 

 that the same stock grown on the same land, 

 for several years in succession, deteriorates 

 considerably ; and, as the vigor of the plant 

 declines, it becomes more and more suscep- 

 tible to tae influence of unfavorable weather. 

 It will generally be found, says the Garden- 

 ers' Magazine^ that in a year of disease the 

 sorts regarded by the cultivator with inter- 

 est as novelties, turn out the best; while 

 those that have been grown on the same 

 spot for several years, suffer most severely. 

 The novelties usually come from a distance, 

 and, irrespective of their intrinsic merits 

 as varieties, they have this peculiar advan- 

 tage, that they were raised on a different 

 soil, and to some slight extent in a different 

 climate from that they are used to depend 

 on for subsistence. 



Generally speaking, says the same mag- 

 azine, the best seed for strong soils is that 

 raised on peat and bog lands, and seed of 

 excellent quality may be obtained from dry, 

 calcareous soils and newly-broken, sandy 

 pastures. It is very much the custom in 

 England for traders who have to provide 

 largely of seed-potatoes for their customers, 

 to send certain sorts to growers occupying 

 such lands, in order to secure vigorous stocks 

 for cultivation the next year on strong, pro- 

 ductive lands. The seed so obtained pro- 

 duces a cleaner crop in a bad season, and a 

 heavier crop in a good season, than seed of 

 the same sorts that has not enjoyed a change 

 of soil for many years. Hence, purchased 

 seed is, as a rule, better than that of the 

 same sort home-grown. 



Microscopic Aspects of the Potato-Dis- 

 ease. — Mr. Wenham, writing in the Micro- 

 scopical Journal on the subject of potato- 

 blight, says that a fungus, from the univer- 

 sal presence of the spores in damp localities, 

 and its rapid growth, may appear simulta- 

 neously with morbid conditions, and yet not 

 be the primary cause. The grape-vine dis- 

 ease, being cuticular, may be readily traced 

 by the microscope to a fungoid origin, and 

 this origin is further proved by the action 

 of the sulphur-cure, so destructive to fungi 

 in confined localities. This is of no avail 

 in the potato-disease, which, under condi- 

 tions favorable to its development, is inter- 

 nal and constitutional. 



On placing a very thin slice of potato 

 (taken at any time of the year) under the 

 microscope, the cells are seen to be filled 

 with starch-granules, and the walls coated 

 with a layer of active protoplasm of the 

 usual molecular appearance. In the healthy 

 cell, this protoplasm, when seen under the 

 highest powers, with suitable illumination, 

 has a vibratory motion, with feeble currents, 

 in various directions. On approaching the 

 vicinity of the diseased portion, the cell- 

 walls begin to appear of a light-brown color, 

 and wherever the least tinge of this becomes 

 apparent there is no movement, nor can any 

 protoplasm be detected adhering to the wall 

 of the cell, which from that time is a dead 

 member. 



Tracing the cell-walls farther, the color 

 deepens, and the septa become thicker, till 

 at last the walls split, giving the now rotten 

 cell a detached appearance; but, from the 

 first indication of disease to the final rotten 

 state, no vital activity can be discovered. 

 In all the phases the starch-granules remain 

 unaltered, completely resisting this peculiar 

 decomposition. The disease is evidently 

 located throughout the tuber, in the sub- 

 stance of the cell-walls. Of its origin Mr. 

 "Wenham offers no opinion. 



English Honors to an American Astron- 

 omer. — The British Koyal Astronomical 

 Society has awarded a gold medal to Prof. 

 Simon Newcomb, Astronomer-in-Chief of 

 the United States Observatory at Washing- 

 ton, for his Tables of Neptune and Uranus, 

 and for other valuable astronomical work. 

 The "Investigation of the Orbit of Uranus, 

 with General Tables of its Motion," is the 

 result of fifteen years of labor under the 

 immediate supervision of Prof. Newcomb. 

 Prof. Cayley, of the Astronomical Society, 

 in presenting the medal to Dr. Huggins 

 for transmission to Prof. Newcomb, spoke 

 in very high terms of commendation of the 

 Washington astronomer, and concluded as 

 follows : " Prof. Newcomb's writings exhibit, 

 all of them, a combination, on the one hand, 

 of mathematical skill and power; and, on 

 the other hand, of good, hard work, devoted 

 to the furtherance of astronomical science. 

 The memoir on the lunar theory contains 

 the successful development of a highly- 

 original idea, and cannot but be regarded 



