STATE llORTlCULTtfRAL SOCtETV* 39 



the same genus (Datana angusi)^— the first eating the foliage of the 

 apple, and the second that of the wahnit, hickory, etc. 



I need not rehearse the symptoms as manifested in these cater- 

 pillars, and will only say that they differed from those of the cab- 

 bage-worm scarcely at all except in the })articular that the apple and 

 walnut caterpillars did not change color — which was doubtless due to 

 their much thicker skins, — and in the fact that decay after death 

 was less rapid and complete. 



Here, as in the cabbage-worms, 1 found in every case of disease, 

 without exception, vast numbers of bacteria belonging to the genus 

 micrococcus infesting the alimentary canal; in the case of the apple 

 caterpillar, the same precise species as that of the silk-worm (Micro- 

 coccus hoitihi/fis J; anil in the walnut cater])illar a Micrococcus which 

 I have not yet been able to distinguish from that of the cabbage- 

 worm, and which I i .Ink to be certainly the same. 



Both these micvococci I succeeded in cultivating, again and 

 again, in beef broth, using, of course, every known precaution 

 against the invasion of my cultvire fluids by other forms of bacteria 

 than those with which the sick larvie were affected. The minutest 

 droplet of fluid from a diseased worm introduced into a flask of beef 

 broth would, in a day or two, render the whole contents of the flask 

 milky with the myriads upon myriads of micrococci resulting, and 

 these were in every case precisely the same as those taken from dis- 

 eased larvffi. Hundreds of microscope slides of these cultures were 

 mounted, and have since been carefully studied by Prof. Burrill and 

 myself, and he has no more doubt than I that these cultures were 

 genuine. 



Next I selected two lots of healthy larvae of the apple cater- 

 pillar, ten in each, set one aside as a check lot, and devoted the other 

 to experiment. The leaves fed the latter were brushed from time to 

 time with the fluid containing the cultivated micrococci, and the food 

 of the other lot was moistened in the same way wdth distilled water. 

 On the 3d it was noticed that one of the worms of the infected lot 

 was stupid and ate but little, and the next day one died, and two 

 others were evidently sick. The dead larva was carefully studied 

 and the silk-worm micrococcus, the same species as that with which 

 its food had been treated, was found in gi-eat abundance in its intes- 

 tines and blood. On the fifth day another died, and on the sixth 

 day another, botli alive with bacteria in the blood and alimentary 

 canal. On the 9th two were very sick, and one of these was killed 

 for examination. It was found swarming with Micrococcus bonibijcis, 

 like all the j)receding. On the 11th day one died, and on the 13th 

 another, lx)th in the same condition. Four davs after, one of the 

 four now reuiaining. which was seen to be apparently sick, was killed, 

 and a droplet of fluid from its alimentary canal was used to infect a 

 test tube of beef broth. In a few days this developed a great quan- 

 tity of Micrococcua bonibijcis. In the mean time one of the examples 



