2l8 



SCIENCE. 



[Vol. XVIII. No. 454 



SCIENCE: 



A WSEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



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N. D. C. HODGES. 



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APPLE AND PEAR SCAB. 



The microscope has revealed the fact that the brown scab which 

 has become so prevalent on certain varieties of apples and pears 

 during recent years is itself a plant, reproducing itself by spores, 

 which are borne upon the wind and find their congenial soil in the 

 leaves, tender twigs, and fruit of the apple and pear. 



When the nature of the pest was ascertained a remedy was sug- 

 gested in the treatment which has recently been discovered to be 

 so effective in the case of other fungoid diseases of plants, namely, 

 the spraying of the affected trees with a solution of copper sul- 

 phate. This treatment has been recommended by the national 

 Department of Agriculture for several years; but, as heretofore 

 practiced, it has often injured the foliage of the trees to such an 

 extent that the remedy was almost as bad as the disease. 



The Ohio Experiment Station has this season conducted an ex- 

 tensive series of experiments, some on its own grounds, some in a 

 large orchard in the neighborhood leased for the purpose, some in 

 the fruit region of the lake shore, and some in orchards along the 

 Ohio River. In these experiments several preventive solutions 

 have been tried, but especial attention has been given to the ques- 

 tion whether the strength of the copper sulphate and lime solution 

 (known as the Bordeaux mixture) might not be reduced so as not 

 to injure the foliage and yet accomplish the object of preventing 

 disease. The results of this work were shown in a striking ex- 

 hibit, made at the State fair and other places, in which sprayed 

 fruit was shown to be almost absolutely free from disease, while 

 that from neighboring trees left unsprayed was almost worthless. 



The spraying not only reduces the injury to the fruit, but it 

 largely increases the total crop. This is because the foliage on the 

 sprayed trees remains healthy, while on the unsprayed trees it is 

 diseased and unable to perform its functions. Furthermore, the 

 scabby fruits fail to develop to their normal size, because of the 

 scab that is on them. The sprayed apples are fully twenty-five 

 per cent larger than the unsprayed, and are more highly colored. 

 As might be expected, the sprayed apples sell for more than the 

 unsprayed, there being a difference of more than twenty-five per 

 cent in favor of the former. This was found to be the case by an 

 actual test in the market, the sprayed apples selling more rapidly 

 at fifty cents per bushel than the unsprayed at forty cents. This 

 makes a total gain in favor of spraying of fully fifty per cent. 

 The cost per tree for the season does not exceed twenty-five cents, 

 while there is often a gain of one dollar or more, depending largely 

 upon the variety, as some are much more subject to scab than 

 ctliers. Spraying also prevents the premature falling of the leaves. 



which is one of the results of the scab, for it affects the leaf as 

 well as the fruit. 



Following are the formulae used in these experiments: No. 1 — 

 copper sulphate, 4 pounds; lime, 4 pounds; water, 1 barrel. No. 

 2 — copper sulphate, 4 pounds; lime, 4 pounds; Paris green, 4 

 ounces ; water, 1 barrel. 



No. 1 is used for apple and pear scab, and to prevent the leaves 

 of plum and pear trees from dropping prematurely; also, for rasp- 

 berry cane scab, or anthracnose. Apply once before the leaves 

 open and about three times thereafter. It should not be used on 

 plums and early fruits later than July 1, and it is not necessary to 

 use it on any fruit later than Aug. 1. It should not be used on 

 raspberries after the blossoms open, and care should be taken to 

 direct the spray to the young growth and avoid the old canes after 

 the fii'st application. 



No. 2 is used on pear, apple, plum, and cherry trees after the 

 blossoms fall, for the purpose of destroying insects. On plum and 

 cherry trees the applications should be made once in two weeks, 

 and oftener if the weather is rainy, up to within six weeks of the 

 time of ripening. For the last application on these fruits, it 

 would be well to dilute the mixture one half, or more, so as to 

 avoid lime coating; or the following may be substituted: Paris 

 green, 2 ounces; copper carbonate, 2 ounces; dissolve in three 

 pints of ammonia; add half a pound of lime and one barrel of 

 water. 



LETTERS TO THE EDITOR. 



»** Correspondents are requested to be as brief as possible. The writer^s name 

 is in all cases required as proof of good faith. 



On request in advance, one hundred copies of the number containing his 

 communication will be furnished free to any correspondent. 



The editor will be glad to publish any queries consonant with the charactt r 

 of the journal. 



The Man of the Future. 



Doctor Langdon"s remarks in a recent issue of Science (No. 452) 

 on the probable further evolution of man is one full of interest 

 to every speculative anthropologist. To the present writer it is 

 evident that man has by no means arrived at the acme of his di - 

 velopment, either mentally, morally, or physically; indeed, I con- 

 ceive the entire genus homo to be but little more than just started 

 upon its career of evolutionary growth. 



In the first place there are many species and sub-species of men 

 upon the face of the globe of very low type that will either have 

 to be, or will be, exterminated in time by some branch of what 

 ultimately will persist as the dominant race. As examples, we may 

 point to the pygmies of Africa, many of our North American In- 

 dians, and similar ferine tribes. Some of these, however, wUl 

 undoubtedly to a certain extent fuse with the root-stocks of the 

 dominant race; some may be assimilated entirely, — a fate that 

 seems to await the negroes of the United States, and perhaps later 

 the Japanese and others. In short, I am inclined to think that, in 

 the ages to come, the human species of this world will eventually 

 tend to form one homogeneous race, and that race will speak but 

 the one language. When that epoch has fully arrived, then 

 indeed will the human species be fairly on the road towards 

 its perfection. Multifarious tongues now stand as a prime factor 

 in the way of man's more rapid evolvement. All this will require 

 an enormous lapse of time, and when it arrives the face of the 

 earth will be greatly changed. Man will have subordinated all 

 things to his will, — and nearly all other forms now existing, with 

 the exception of the very few that may prove useful to man, will 

 have been completely exterminated. 



Many of these changes are now slowly advancing Under our 

 very eyes. Take the ideal man of the present day, — one of the 

 most perfectly organized ones as they now exist, and what do we 

 find ? In the vast majority of cases, as Clevenger has shown, he 

 is still subject to a variety of diseases which arise from the fact 

 that within a comparatively recent time of the world's history he 

 has assumed the erect attitude ; has passed from quadrupedal to 

 bipedal locomotion. Often these diseases prove to be fatal, — as 

 prolapsus uteri, the hernias, and others : is there to be no improve- 

 ment along this line ? Again, he has still clinging to his organi- 

 zation many of the structural vestiges that link him with the 



