s II m m a r y. 



La-si \ car i had v,n occasion to situdy the s. c. polyhedral discas 

 oi the caterpilUrs of the nini-moth Wihi-ch destroyed iai a terrible 

 manner many himdrcd miles of beautiful forests in Cechoslowakia. 



A short review of the whole calamity, which arrives this year 

 its culmination gives the same exipeirie-nces which nie m.atde for- 

 merly in all such cases. 



Insect parasitiîig m nun-moth h.ad not efficiency except ilie 

 lachinidae, which killed only SO^r of the nun-catenpillars oi' 

 puppaie. 



Also the birds as enemies had no success. \Ve made again 

 iiie persuasion that the only help against this calamity is the infec- 

 tions pest well-known as polyhedral-diseass. 



1 undertook the investigation of that wilt n ilie liope of obtai- 

 ning results of economic importances. 



I proposed to discover two highly important and hitherto un- 

 k no Win things. 



1. What a microorganisniius cadises the polyhedral diseass. 



2. In wjiich manner we could spread it artificially and if it wo'uld 

 he successful. 



riic first Question 1 studied especially on itiicroscopical sections 

 tl. rough the body of ill caterpillars. The whole course of this wilt is 

 as follows. 



The first sign of the begmnmg of »polyhtdrie« is, that the nu- 

 ciei in peritracheal tissne and in the hypederm.is begin to increase 

 and to transform their chromatic substance in few spbericalballs. 

 A short time after, we see appear the first polyhedral-bodies among 

 the chromatic iparts. They are 2 u large and increase slowly till 

 to 6 u. To'getlier with disoippearing of chromatin begin nov/ the 

 polyhedral crystalls be more and more numerous. 



At least we see: Jhe imimensely e.vtented nuclei densely sto.p- 

 !jed with !)olyhedral bodies fill the cells that only a narrow stripe 

 01 degenerated Protoplasma persits along the cell-membrane. In 

 the centre of the nucleus remains a rest of chromatic substance. 



In this chromatic rest or everywhere among the polyhe drieiíš,, 

 arid later also in blood we can see after a proper praeparation very 

 many little points, which seem to be the same as the Ghlamydozoa 



