STATE HORTICULTURAL SOCIETY. 3< 



We can conceive sometliing of the signilicance of this disease 

 if we imagine the terror and dread which would seize mankind if 

 such a phigue shouhl suddenly assail human life. \\ hole towns w^ould 

 be de])()i)uluted, and tlie dead would rot in the streets by hundreds. 

 There would be no escape for any, because the contagion would be 

 conveyed by the very food and drink by which life was sustained; 

 the fountain of life itself would be poisoned. 



This disease of the cabbage worm first came to my notice on the 

 11th of September, wdien an assistant, who had been sent into the 

 field for larvae for experimental use, brought in one which had ap- 

 parently been dead for some time, and was blackened and somewhat 

 shrunken. ()u dissection, the intestine was found full of uiuligested 

 food aiu] swi.rming with bacteria of a species wliich \ afterwards 

 came to recognize as those characterizing schlaffsucht in the cab- 

 bage worm and also in a caterpillar (Ddtana anf/Hsij which eats 

 the leaves of walnut and hickory. These were excessively minute 

 spheres, ^-^ha^ of an inch in diameter, sometimes single, sometimes 

 in pairsand occasionally in strings of from four to eight. The 

 same day two lots each of t^\:enty-five he.dthy worms of various 

 ages, most of them about to transform to pupa?, were placed in 

 breeding cages for use in an experiment of which I need say noth- 

 ing further since the occurrences about to be described made it im- 

 possible to carry it out. It was noticed that some of these worms 

 were paler than others, and soon these became torpid and quit their 

 food. On the loth one died, on the 16th another, on the 17th 

 seven more, some of these being mere deliquescent masses of rotten- 

 ness within twenty hours from the time when their health was ap- 

 parently perfect. And so, all went. Of ninety cal)bage w'ornis 

 brought to tlie laboratory, fed regularly and carefully attended, only 

 four or five ever reached the pupa stage, and not one of these 

 emerged as a butterfly. 



In the meantime the same plague was raging scarcely less de- 

 structively in the open air. Not a field visited anywhere about 

 Bloomington or Normal was finally free from it. Prof. French wrote 

 me of its occurrence at Carbondale, Prof. Burrill henrd of it at 

 Champaign, I found it in cabbage fields near Chicago, and a corre- 

 spondent in Michigan also found it there. Later, as already men- 

 tioned, it reached Stark and Fulton Counties to the westward. Dur- 

 ing this time we made most careful microscopic studies of twenty- 

 eight specimens in various stages of disease, besides several of 

 healthy worms, examined for comparison. All these diseased indi- 

 viduals, whether in field or laboratory, agreed in several particulars; 

 and differed in these same particulars from the healthy ones. 



Among them were the pale color, sometimes followed by a par- 

 tial blackening of the skin, the torpidity and loss of appetite, the 

 sluggish digestion, (the intestines of dead larvae being usually full of 

 green food scarcely altered since it was swallowed ). and the presejice 



