18 REPORT OX THE DISEASES OF SILKWORMS IN INDIA 



and accurate as could be wished. This little organism is called a 

 " planont." 



The planont moves by a peculiar creeping mode of locomotion 

 called amoeboid. It passes through the peritrophic membrane 

 (Text-fig. B), assisted most probably by the production of some 

 dissolving or digesting substance, and finally penetrates the gut- 



Text-figure C. Diagram of dissection of caterpillar (From Mailott et Lambert). 



A-A, Dorsal vessel or heart. B-B, Gut. C, Silk-gland. D, Nerve cord. E, Reproduc- 

 tive organ, a, Salivary gland, b, Excretory tube. Hsemocoele is black. Note junction of 

 fore and mid gut just in front of " a " and of mid and hind just behind " b ". 



wall proper. It seems almost certain that at this stage in the 

 infection the planont in its journey gets no further than the gut- 

 wall : the firm muscular basal membrane to the outside of the gut 

 seems to defy further progress.* At all events if the guts of infected 

 silkworms are examined during the first few days after infection, the 

 parasites are practically always, if not always, found in the epithelial 

 cells of the gut-wall. It seems to me highly probable that the 

 planont is furnished with an initial amount of energy which suffices 

 to take it through the peritrophic membrane and into the gut- wall, 

 there the initial energy gives out or the necessary stimulus to further 

 advance ceases and the planont comes to rest. The organism after 

 its wanderings are ended is called a meront. It is as a rule a com- 

 pletely rounded organism with one nucleus (Text-fig. A, 7). 



What finer changes go on inside the planont during its wander- 

 ings are not of much practical importance, but it may be stated 

 that the two nuclei which we noted in the organism in the spore 

 seem to fuse together to form one nucleus either just before or just 

 after leaving the spore case. At all events in place of two nuclei 

 the planont has only one. Some workers profess to have discovered 

 evidence that the planont in its wanderings before entering the 

 gut-wall multiplies by dividing into two, which two again multiply 

 by dividing into two and so on. I am much more inclined to believe 

 that each planont instead of dividing into two fuses with another 



* According to Stempell the planonts go right through the gut-wall into the " body cavity " 

 and then turn back and attack the gut-wall — obviously a foolish proceeding and one which I 

 cannot believe in. If they did this why are organs in the " body cavity " not attacked at the 

 same time as the gut ? 



