302 Captain T. Hutton on the 
Mr. Cope, in a Lecture on Silk delivered at Lahore, gives (as 
before mentioned) from twenty-eight to forty days as the time 
consumed. If B. Morispins its cocoon in twenty-eight days from 
the time of hatching, a stronger proof of the total unfitness of the 
Punjab climate for the culture of that species could not be 
furnished. The fact, however, is that the time laid down in 
the lecture cannot satisfactorily be applied to any species in 
particular, but evidently includes more than one. 
The Chinese account likewise would appear to have reference 
to more than one species, while in Madras, the species referred to 
by Dr. Anderson was in all probability one of the three monthly 
worms, because the true B. Mori is nowhere cultivated below 
the North Western Provinces. 
The true time consumed from the hatching of the worm to the 
completion of the cocoon would, consequently, appear to range 
from thirty-six to forty-six days, and the more rapid progress 
made in Europe is probably to be attributed to the fact of the 
worms being shut up in rooms with a temperature of 68° to 77°, 
which is altered after every change of skin, Thus, Dewhurst 
says, ‘75° is the degree of heat they should be kept in until the 
first casting or moulting; between 73° and 75° until the second 
moulting; between 71° and 73° until the third ; and lastly, between 
68° and 71° until the fourth moulting.” 
From this statement we perceive that, according to this writer, 
the temperature should be reduced as the worm advances to 
maturity, a procedure which is diametrically the reverse of that 
pursued by nature. 
According to the same authority “it has been proved by a 
series of experiments that in France 68° is the heat most suitable 
to silkworms ; some cultivators have raised it as high as 77° with 
good success, while M. Boisseur de Sauvages has even gone as 
high as 100°.” 
At Mussooree I have always reared the worms in an open 
room, so that, as the external temperature varied, that of the 
interior varied likewise, and the air was always fresh and natural. 
The eggs hatched spontaneously in a mean temperature of 64°, 
and the thermometer never rose beyond 68° up to the time of 
spinning the cocoon. During the same time the daily mean of 
the external temperature ranged from 47° to 66°, so that the 
French view of the matter is thus proved to be the most correct. 
1 have shown, moreover, (ante, p. 152,) that 1 found great difficulty 
in checking the hatching of the eggs even in a temperature of 53°, 
and only did so at last by placing them out all night in the frosty 
air of December, at an elevation of 5,400 feet. 
