Ctn.T¥BE OF SILKWORMS. 
onable to spin properly, for examination, as these feeble indivi- 
duals are sure to show disfaso, if present at all in a brood. All 
tliose ihiit I examined under the microscope weni swarming with 
panhidophyion ovatum, of Lebert. the bacterium which causios 
jH'brine, the worst disease to whifi silkworms are liable, as it 
is Dot only infections but hereditary. This disc^ase could have 
no sort of connection with the mulberry leaf disease, but must 
have been importttd from China, either in the eggs or by means 
of infected trays or cocooning frames, whicli were all broiii^lJ. 
from China, or' it may have l>een contracted in the way which 
will Ik! mentioned hereafter. Ou previous visits that. I paid to 
Ayer Kuniug I bad l>et:n assured by the Clmiese that they bad 
bad no deaths amongst their worms, but financial reasons may 
account for their not giving correct information on this point. 
The micro-organism causing the disease is thus described 
by Mr. E. M. Crook shank in hia Practical Bacieriology : — "Pan- 
kwtophyion o-vahmr Lebert {nogeina homhyciSf micrococcitB ovatuet 
corp^mUs du ver a soie), shining oval cocci, J to ^ mm. long, 
,7^j mm. wide, singly and in pairs, or masses; or rods, mm. 
thick and twice as loug. They multiply by sub-division. They 
were ex|>erimentally proved to be the cause of pebrine, gattinet 
maladie des corpusdes, or JiecJ^micM ; and were discovered in the 
organs of diseased silkworms, ae well as in the pui>se, moths, 
and eggs." 
I have not detected any of the three other principal silk- 
worm diseases— grasserie, muscardine and liaeeidity — amongst 
the worms in Perak. 
FAILUItE OF THE CULTIYATORS. 
After rejwated losses caused by the death of whole brof>ds 
of worms, and by the much reduced quality of the silk yiehled 
by the silkworms, lx)th the original Chinese cultivators and Mr. 
Light abandoned the attempt of cidtivatiug them in Febiimry 
of 1892, after having made a frt^sh imjwrtation of eggs from 
China at the end of 1891. These, however, as they were reared 
in the same rooms and on the same trays as the old ones, natujully 
contracted the disease and aim died out. 
EXPERIMENTAL BREEDIKG TO ELLBflKATE THE 
DISEASE. 
On 10th Septemljor, 1891, 1 wrote as follows on tliis subject : 
" Having proved the existence of pebrine amongst the worms here, 
it is a subject for the eonsitleration of Govemmimt whether (a) 
they will take any mejisnres to stanxp it out, or (h) let the intro- 
duction of silk-growing in Penik become a failure, as it most 
surely will without Govemmetit intervention. 
