308 
The Microscope in 
rMonthly MIcroscoiMcal 
L Juuinal, May 1, 1869. 
Iii lot 35 of 1268 moths 345 were of the best character. 
Thirty-eight were less fine specimens, and 885 were of couples 
separated by the " cellular method." It is with these excellent ova 
that MM. Levi await the harvest of the ensuing year. M. Cri- 
veUi has been equally fortunate with the lot isolated in the manner 
before referred to. 
It is difficult to establish a proportion between the disease as it 
appears in the egg and as it afterwards exhibits itself in the moths, 
because of the different periods at which the examination is made. 
If the examination be made too early, it may discover 0 per cent, in 
the chrysalides ; 30, 50, or 60 per cent, in the moths ; and, again, 
0 per cent, in the eggs proceeding from these. These proportions 
have been found by M. Crivelli. The corpuscles are propagated 
vdth an incredible rapidity, and sometimes in the last moments of 
the life of the chrysalides, when the eggs are already formed — a 
fact which explains why a great number of corpusculated moths 
may present eggs which contain no corpuscles. 
In the experiments in "cellular" breeding it has been found 
that the males hardly ever propagate the disease to the females. 
In the tables prepared by M. Crivelli, where the male was diseased 
and the female healthy, the eggs also were invariably healthy. Is 
it that the spermatozoa enter the ovum by a channel which does 
not allow the passage of the corpuscles ? From observations which 
1 have conducted, I deduce that the disease in the ova is to that of 
the moths as 1 to 10. Here are some examples of this : — 
No. of 
obser- 
vation. 
Eggs. 
Moths. 
Number of 
eggs 
examined. 
Number 
of eggs 
affected. 
Percentage 
of 
disease. 
Individuals 
examined. 
Diseased 
specimens. 
Percentage 
of 
disease. 
1 
2 
3 
4 
50 
50 
75 
45 
4 
3 
7 
4 
8 
6 
9 
8-9 
20 
20 
15 
20 
16 
12 
14 
17 
18 
60 
95 
85 
From the foregoing remarks and general experience, I draw the 
following conclusions : — 
(1) . An egg, apparently healthy as to its microscopic features, 
may proceed from very unhealthy parents. 
(2) . An egg, healthy as to its characters under the microscope, 
may and does give ordinarily a long produce in cocoons, but it may 
be incapable of giving healthy eggs. 
(3) . The absolute health of an egg proceeding from healthy 
moths [which present only about 4 or 5 per cent, of diseased speci- 
mens] is an excellent indication of the capacity of an egg to produce 
