Junes, i9i8 Bacterial Disease of Gipsy-Moth Caterpillars 521 



Gelatin colonies. — Growth slow, colonies very small and majority under surface. 

 Surface colonies round, slightly convex, edge entire, no liquefaction. 



Nutrient agar colonies. — Growth slow. Majority of colonies under surface and 

 oblong. Surface colonies round, smooth, convex, edge entire, internal structure 

 finely granular. Diameter 0.25 to 0.33 mm. 



Potato agar colonies. — Growth rapid. Majority of colonies under surface and 

 oblong. Surface colonies round, smooth, convex, edge entire, internal structiu-e 

 finely granular. Diameter i to 1.5 mm. 



NH3 production. — Absent. 



Nitrate solution. — Nitrates not reduced. 



Indol production. — Absent. 



Hydrogen sulphid production. — Absent. 



Fermentation of carbohydrates with formation of acid and gas. — 



Gas. Acid. 



Dextrose o + 



Levulose o + 



Saccharose o + 



Maltose : o + 



Lactose o + 



Mannit o + 



Adonit o + 



Dulcit o + 



Oxygen requirements. — Facultative anerobe. 



Best media for cultivation. — Solid: 1.5 per cent, neutral potato agar. Liquid: 

 Neutral nutrient bouillon containing a carbohydrate, especially bouillon containing 

 about I per cent of saccharose, maltose, or mannit. 



Pathogenicity. — Pathogenic to the caterpillars of the American, European, and 

 Japanese races of the gipsy moth {Porthetria dispar Linnaeus). Not pathogenic to 

 silkworms {Bombyx mori Linnaeus) and army worms (Cirphis unipuncta Haworth) when 

 fed per os. Guinea pigs, rabbits, and human beings when fed pure culture per os 

 not affected. 



SUMMARY 



(i) In 191 5 a new infectious disease was found in certain cultures of 

 the Japanese race of the gipsy moth. 



(2) The infection spread later to cultures of the American race. 



(3) The disease is clinically, pathologically, and etiologically distinct 



from wilt. 



(4) A streptococcus was found to be the causative agent. 



(5) The bacterium is new to science and is kere described under the 



name "Streptococcus disparts." 



(6) During the early stages of the disease the bacterium is found 



throughout the alimentary tract of the gipsy-moth caterpillars. 



(7) During the later stages of the disease and after death the bacterium 



invades practically all the tissues. 



(8) 5. disparis invades the alimentary tract with the ingested food. 



(9) Healthy animals naturally become infected by eating food soiled 



by the feces of infected animals. 



