36 
as those of higher animals. The germs of disease were un- 
doubtedly brought in contact with the grasshoppers many 
times, but they failed to gain a foothold. 
BACTERIAL DISEASE OF CABBAGE BUTTERFLIES. 
On Aug. 21 several] dead caterpillars of our common cabbage: 
butterfly (Pieris protodice) were found clinging or rather cement- 
ed, to the leaf of the rape-plant on which they had fed, The 
appearance presented by these caterpillars was quite different 
from that of the ordinary healthy ones. The skin was brown 
and shrunken, and the whole body greatly flattened, clinging 
closely to the leaf. Around the body of one was an incrusta- 
tion composed of dried body-fluids full of bacteria. This help- 
ed to cement the decomposing body to the leaf. On tearing 
open the body and examining some of its fluid-contents, it was 
found to be teeming with bacteria of several kinds. 
An experiment was made to determine the practicability of 
spreading the disease by contact of healthy worms with the 
body-juices of dead and diseased caterpillars. Thirteen heal- 
thy cabbage-worms were procured, and their bodies were 
moistened with the macerated bodies of two diseased larvee, 
chiefly along the breathing pores and on the mouth. They 
were then placed in a cage with rape. On Aug. 23 seven of the 
larvee were dead, and of the others two had pupated and four 
were unchanged and alive, although not bright in color. On 
Aug. 25 three of the four were dead with the disease and one 
had pupated, making ten killed and three pupated in four days. 
The caterpillars attacked by the disease first become inactive 
and show a general lack of vitality. The color looses its 
freshness and becomes dull, followed by a reddish and 
then by a brown shade, which is finally succeeded by a deep 
reddish or brownish black. The body during these changes 
often becomes mottled. The interior of the body gradually 
breaks down, until by the time its skin becomes brown it is a 
mere bag or skin full of putrid matter. The body now flattens, 
as the caterpillar dies clinging closely to the leaf, until a rup- 
ture occurs, usually caused by its own weight, when the fiuid- 
contents pour out and form a dark brown or black stain across 
the leaf over which they flow. During these changes the 
body of the caterpillar often clings with its fore-legs, allowing 
