226 KEPOKT OF THE COMMISSIONER OF AGKICULTUKE. 



allel wires stretched across the room at about 13 inches apart. M. 

 Pasteur suggests that a simple piece of cloth about 4 inches square be 

 used instead of the sack. The moth lays her eggs on tliis and is then 

 retained by being fastened to the cloth, the corner of which is turned 

 up over her and a pin i)assed through it and over her wings. Some 

 trouble has been experienced by this process, as the eggs, if not proi)er]y 

 gummed to the clotb, will sometimes fall off and be lost, and the moths, 

 not being confined as in the sacks, will wander to other clotljs ami 

 get their eggs mixed with those of other moths, which would be detri- 

 mental to the microscopical selection to be hereafter described. It hiis 

 the advantage, however, of enabling the microscopist to avoid tlui labor 

 of turning the sacks. 



The moths emerge from the cocoons, as a rule, from 5 to 8 o'clock in 

 the morning, At the latter hour many of them will be found coupled 

 and clinging to the chains. These should be carefully taken by the 

 wings and placed upon a table by themselves, the single moths being 

 ph^ced upon another table #where they will couple if the sexes are 

 evejdy divided. They should then be transferred to the other table as, 

 the lluttering of the male moths is apt to disturb the couples. These 

 should be left together until 4 or 5 o'clock in the afternoon, when they 

 nuiy be separated by drawing them gently apart by the wings. The fe- 

 males should then be placed in the cells or upon the cloths already de- 

 scribed, where they will at once commence their egg laying, completing 

 it in about thirty-six hoars. Most of the males may then be thrown 

 away, thougli it 'may be wise to keep a few of the more active ones to 

 compensate for any su])erbundanceof females in the issue of the follow- 

 ing day. But little dithculty will be encountered in distinguishing the 

 sexes, the males being noticeable by their smaller abdomens, more ro- 

 bust autenuie and by their greater activity. 



When the eggs have been laid, the microscopical examination of the 

 fuotlis should be made with a view to ascertaining whether or no they 

 are afQicted with pebrinc. The entire moth should be ground up with 

 a few drops of distilled water in a small glass mortar (2-ounce is a con- 

 venient size). A drop of this water is then taken with a medicine drop- 

 per and placed upon a glass slide with a cover-glass over it. It is tlien 

 micro'scopically examined with a power greater than three hundred di- 

 ameters. Plate III, Fig, 2, shows a field very highly charged with the 

 corpuscles of the pebrinc. When the moths are allowed to lie before 

 examination for some time after their death, they will be found to con- 

 tain other germs peculiar to putrefaction. These do not indicate any 

 disease that would affect the egg or its issue; nor does their presence 

 imply any lack of vigor in the parents. They are simply post, mortem 

 parasites. Great care should be taken in cleansing the mortar, pestle 

 and other implements before making an examination, by washing them 

 in an abundance of water and rinsing them thoroughly with distilled 

 water. In making the above examination only the corpuscle oipebrine 

 need be looked for. The bacilli and ferments of llaccidity are rarely 

 found in the moth. 



The corpuscle of the pdbrine is generally oval, though sometimes pear- 

 shaped in form, being from 3 to 4 /z * on its greatest axis and about one- 

 half that length on the shorter. It is generally found singly The fer- 

 ment of llaccidity is usually found in short chains, whose links, almost 

 spherical, have a diameter of about 1 fjt. The two organisms were very 

 generally confounded twenty-five years ago, and much confusion yet 

 prevails among writers in reference to them. 



* 1 /i = 0.001'"™ = 0.00004 inch. 



