Inv.ntion by Chinese Specialist There have been two methods used in testing for Pebrine disease in silkworm vp to this time, one Japanese and the other European. Both have serious drawbacks and it was to overcome these that Prof. C. L. Chien of the College of Agriculture and Forestry, _University of Nanking, recently invented a new egg laying box.
In testing for the Pebrine disease it is necessary to examine every moth after it has laid its eggs. This is done by grinding up the moth in a mortar and then examining the liquid under the microscope. If disease is present the eggs of the moth are thrown away In the Japanese method, when the moths are ready to lay eggs, metal rings are placed on cardboard sheets and the moths are put inside., After the eggs are laid the moths are placed in paper bags, the bags and the eggs on the card being given corresponding numbers. After testing, the eggs from diseased moths are destroyed.
The two great disadvantages of this method are (1) that the moths are separated from the eggs before examination thus increasing the danger of error in numbering, and (2) the eggs, laid on a fixed cardboard paper, must be removed with part of the paper attached with the aid of a knife which not only takes time but also mars the appearance of the card.
By the European method the moths are made to lay their eggs in paper bags. They are kept with the eggs until the time of examination. The eggs from diseased moths are then destroyed and the disease-free eggs are soaked loose from the paper bags and after drying are placed in small boxes. This has several disadvantages to the Chinese farmer, the chief of which is the fact that they cannot be hatched according to the common method, which is to place the card of eggs next to the human body.
Two Mernops CoMBineD, The box invented by Professor Chien is a combination of the above methods. It is round and has a piece of loose paper in the bottom on which the moth lays her eggs. The box has a lid and has holes on the top for ventilation. The moth and eggs are kept together in the box until examination time. The loose paper containing the good eggs is removed and pasted on a cardboard and the diseasea eggs are destroyed. The boxes may be used during successive years.
The new egg laying box, then, keeps the good features of the Japanese method in having the eggs on cards and does away with the objection of not keeping the eggs and moths together until examination time. It preserves the good feature of the European method in keeping eggs and moth together until examination time and does away with the objection of preserve
Text read from the printed page and cleaned; old type leaves the occasional error.