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(2) So far as can be determined by the most careful microscopical 

 study and bacteriological tests, neither fungi nor bacteria are present 

 in the earlier stages of the disease. 



(3) As the disease progresses various fungi and bacteria may appear, 

 but their presence is not constant. 



(4) Infection experiments with bacteria and fungi, especially with 

 the srerm described as Bacterium dianthl. carried out under the most 

 rigid bacteriological conditions, resulted negativel}'^ in every case. 



(5) A disease having all the characteristic symptoms of the so-called 

 " bacteriosis " except the presence of bacteria, is produced by the 

 punctures of aphides, as was repeatedly demonstrated by colonizing 

 these insects on carnations. 



(0) That aphides and not bacteria are responsible for the trouble is 

 shown by the fact that the injuries produced are not accompanied in 

 the earlier stages b}^ fungi or bacteria. The aphides therefore can not 

 be looked upon as simply carriers of some fungus or bacterium, as 

 they produced the disease on j)lants growing under perfectly antiseptic 

 conditions as quickl}^ as upon those not protected hx antiseptics. 



(7) Injuries similar in many respects to those produced by aphides 

 also result from the attacks of thrips — insects which are often present 

 on carnations growing under glass, although sometimes overlooked by 

 growers. Another form of the disease is produced l)y red spiders. 



(8) No matter how badly diseased plants may be, if otherwise vigor- 

 ous they will grow out of the disease entirely and the young leaves 

 and shoots will remain free from spots if kept completely free from 

 aphides, thrips, and red spiders. 



(9) As the disease is not due to bacteria the name "bacteriosis" is 

 inappropriate and therefore stigmonose is suggested for the trouble. 



(10) The carnation is readily influenced by the conditions under which 

 it is grown, and as a result its rea(-tion to the injuries of the aphides, 

 thrips, and spiders, and its susceptibility to their attacks, not only varies 

 in different varieties, but also in individuals of the same variety. 

 Plants grown under improper conditions, therefore, show more of the 

 characteristic injuries from a given number of punctures than do 

 plants growing where all the conditions are favorable. Certain plants 

 rich in oxidizing enzyms have been shown to react more quickly to the 

 work of puncturing insects and mites than plants poor in these enzyms. 



(11) The size of the spots made by the punctures of aphides increases 

 in proportion to the rapidity of growth of the leaf and the suscepti- 

 bility of the plant, and also depends to some extent on the genus and 

 the species of insect which makes the puncture. It is believed that 

 the insect injects some irritating substance of an acid or enzymic 

 nature into the wound, that this sul)stance causes the increase of oxi- 

 dizing enzj-ms in the cells Avhich it reaches, and that these enzyms 



