70 



THE TROPICAL AGRICULTURIST. 



[July 2 , 1883 



PEAR-TR'SE "BLIGHT." 



BY CHAS. D. ZnUtEKJtAN, BOFFAI.O, N. Y. 

 » » » « 



In 1880, Professor Burrill announced that "blight"' in 

 the pear, apple, and quince was caused by bacteria, the 

 smallest living organism known. He found thnt they de- 

 stroy the stored starch grains, causing the same to fei-ment, 

 leaving the cell structure apparently unharmed. 



With the poisoned sap lie inoculated healthy trees, of 

 which over SL^ty per cent showed signs of " blight, '' clearly 

 proving that bacteria is the cause and not the etfect of 

 the disease. No counter evidence has been brought against 

 these experiments of two years ago. 



About twenty years ago, Derlaine stated that bacteria 

 belonged to the vegetable instead of the animal kingdom, 

 as was the belief up to that time, and oaly a few years 

 since it has been proven that they attack and destroy living 

 matter. They increase by " fission," dividing in the middle, 

 under favorable circumstances, once every hour, and some- 

 times even oftener. Once an hour would be at the rate 

 of .sixteen and a half million in twenty-four hours. A few 

 .species are also perpetuated by spores, like fungi. The 

 most favorable temperat>:re for their rapid development 

 appears to be about 95 ° Fahrenheit, together with plenty 

 of moisture. 



Remedies: Eternal vigilance and a sharp knife. Carbolic 

 acid is extensively used to destroy bacteria; it may be 

 diluted with 1,000 parts of water to one of the acid. 

 Quinine is also used. C'old does not kill them, but activity 

 ceases at or nearly the freezing point. Frische claims that 

 123 ° Fahrenheit below zero will not kill them. In the 

 adult state most bacteria are destroyed ni water heated 

 to 1.50° Fahrenheit; spores have been known to survive a 

 short immersion in boiliug water. 



I have often prevented the increase of poisoned parts 

 by carefully cutting otf the outer bark with a sharp knife, 

 and applying linseed oil. This must be done very soon 

 after the appearance of " blight." 



In the case of contagious diseases among animals caused 

 by bacteria, it has been found that the bacteria may be 

 cultivated, whereby it loses most of its poisonous qualities, 

 and animals inoculated with it take the disease in a mild 

 form and are ever after free from that disease. 



Now let us hope tliat some genius will contrive a way 

 to cultivate the species of bacteria under consitleratiou, so 

 that by inoculating^ petir trees with it they woidd be 

 "blight" proot. This would open a field for a new pro- 

 fes.sion — a tree doctor. — The Gayde))ef^^ MontliliJ SorticiiU- 

 itrittt. [Query ? Can bficteria have anything to do with 

 "canker" in cinchonas? — Ed. T. yj.] 



THE NEW SILK CROP IN CHINA. 



It is always extremely difficult to estimate the outturn of 

 the silk crop in North China. We have to reply upon 

 the reports furnished to us by the Chinese who are engaged 

 in the trade of selling silk to foreigners, and the informa- 

 tion wliich they give us varies considerably. At this tune 

 last year the estimate of the crop of the season which is 

 just closing ranged from 6.5,000 to 80,000 or more bales. We 

 ourselves had reasons for estimating 65,000 bales, and even 

 those low figures have proved somewhat in excess of the 

 actual receipts. Had prices, however, advanced here we 

 might have had some 10,000 bales more offered ; but in 

 any case the (quantity would have been much under the 

 expectations of the most sanguine. The cocoons turned 

 out to be light, and thus the anticipations as to the crop 

 proved erroueous. It now seems improbable that the silk 

 crop for 18«o-84 will give more than from 42,000 to 45,000 

 bales for export. Had the weather been favourable dur- 

 ing the last month there was every probabiUty that the 

 amount of silk available to foreigners would have been 

 close on 100,000 bales, as the quantity of seed that had 

 been laid down for this season was very large. But in 

 order to produce such a large crop the most fortunate 

 circumstances were necessary ; clear, settled weather, with 

 a great deal of bright simshine, and no thunderstorms 

 or damp, heavy, days. Now, during the critical time in 

 silk culture this season ^ve hive had weather the reverse 

 of what was de.su'able, the sky having been overcast, with 

 many wet and cold days. It makes the most serious 

 difference in the crop when the mulberry leaves are not 



thoroughly dried in the sun, as too much moistui'e in 

 them makes the young worms sick. The news from all the 

 producing disti'icts, except Kahing, is bad as regards the 

 qumtity of silk produced, and although a considerable 

 advance in prices might bring more sili on our market 

 than the amount we have estimated, there is little to make 

 us anticipate such an improvement in the home trade as 

 would lead to this. Of the silk produced in China about 

 one half is usually offered to foreigners, though this quan- 

 tity is increased whenever the prices are high. But the 

 last telegrams received from London report very favour- 

 ably of the prospects of the European silk crop, while 

 there is a large stock of China silk in Loudon — the re- 

 quirements of the trade now-a-days being taken into ac- 

 count — with reserves at Lyons, Marseilles, Milan and 

 other places. Here, too, the policy of the Chinese specula- 

 tor who has disturbed our market during the last two 

 seasons, has established a reserve of 15,000 to 16,000 

 bales of old silk ; and the knowledge that sooner or later 

 these accumulations must be sold will prevent any consider- 

 able speculative advance in prices, such as would otherwise 

 have occurred. The home trade now requires much le~s 

 China silk than formerly. Many excellent fabrics which suit 

 the fashion of the times are now made out of waste silk. 

 Surahs, made up from waste, have vastly reduced the cost 

 of clothing women and childreu, while there are endless 

 varieties of mixed fabrics, composed of a little silk with waste 

 and cotton, which have ousted from their position the hand- 

 some and genuine silk dresses of former times. The laces, 

 velvets and brocades which are now so much worn can be 

 supplied from the carding ;-oom instead of the filature ; and 

 one effect of all the changes and improvements in the silk 

 piece goods trade at home is that the export of waste silk 

 from all Chiua and .Japan has advanced to 60,000 piculs per 

 annum, from the 20 to 25,000 piculs which were sent a very 

 few years ago. 



The English and French markets for China silks were 

 very disappointing last season, chiefly owing to the fashions 

 in Europe and America requiring silks of cleau, even, sizes, 

 such as are made in the filatures here. France, Italy, and 

 Japan give large suppUes of that kind of .silk; and con- 

 sequently the prices obtained for Chinas were low. China 

 silk is likely to be less used at home every year until it is 

 properly reeled, and as soon as this desirable condition has 

 been brought about it will regain its old high position in the 

 European markets. China cocoons make the firmest reeled 

 silk and the best quality, and our siik has been brought to 

 its present degraded position in the estimation of foreign 

 manufacturer.s, bythestuiMd inattention to the requirements 

 of trade which the native silk men have all along displayed. 

 There are many persons who are throughly acquiiinted with 

 the" silk trade, ivho see little or no hope for the future of 

 China silks, except in the establishment here of filatures 

 on a large scale. They say that the Chinese will not im- 

 prove the reeling of the silk, and that either their own 

 ignorance, or the action of their riders, prevents their ac- 

 -quiring that iuformation which would enable them to 

 rectify the carelessness or mistakes which are ruining the 

 trade. Cheaply reeled and coarse silk are no longer suit- 

 able to the goods that are produced in Franc. All this 

 time, while the deterioration that h.is taken place in the 

 quality of China silks is being carefully maintained by the 

 native.s and protected by the mandarins, other countries are 

 bestowing increased care and capital on seri-culture. Great 

 attention is being given to it in India, America and New 

 Zealand, while Italy is extending every year the cultivation 

 of the mulbery tree. In Per.sia. also, efforts are being made 

 to revive the silk industry. The discoveries of M. Pasteur, 

 by which he enables silk farmers to separate the good from 

 the bad or inferior seed, have already had an important effect 

 on the industry in France. Anything which lessens risk, 

 and makes more certain a business with which chance has 

 hitherto seemed to have so much to do, must improve it 

 and draw to it more attention and capital. All these things 

 pass unheeded by the China silk dealers, its cultivators, and 

 the rulers of the land. 



(Com municated.) 

 It is too early yet to speak with certamty as to the ex- 

 tent of the North China silk crop, as so much depends 

 on the quality and out-turn of the cocoons produced ; it 

 is, however, well known that the year's cro]) has bee,j 



