188 PHYTOPHTHORA PARASITICA. 



trouve en abondance." I have found these palmately branched 

 hyphse in the cortical parenchymatous cells and growing away from 

 the fibro-vascular bundles. The leaves and the growing point 

 were not attacked when the seedlings gave way at the collar on 

 being diseased. On the 24th another seedling from Lot B was 

 diseased. The third remained healthy for a week more and then 

 this part of the experiment ended. The seedlings from Lot A got 

 attacked at the surface level of the soil one by one, till the 

 majority of them died. The attack was never found to come 

 from the roots upwards. It invariably began at the surface level 

 of the earth in the pots. 



All the pots of the Lots A and B, with some of the diseased seed- 

 lings were then kept in a moist condition in the laboratory. On the 

 30th of August one pot from Lot A was again sown with ten castor 

 seeds. By the 5th of September eight seedlings died of the attack 

 on the surface level. One of the two remaining seedlings was 

 slightly attacked at the same place, but it succeeded in the struggle 

 for existence. The other was not at all attacked. 



It is needless to say that for all these experiments " checks " 

 were kept in exactly the same condition, except that the earth was 

 not from diseased areas. 



On the 30th of September a second pot of Lot A was sown with 

 castor seeds, i.e., two months after the seedlings in this pot 

 died of the attack. The seeds germinated after a week, and the 

 seedlings grew into big plants without any being in the least diseased. 

 This shows that the fungus in the soil was not able to retain its 

 vitality for two months. 



hese experiments have proved interesting first because seed- 

 lings have been found to be attacked at the surface level of the 

 earth got from diseased areas, while in the fields the attack has not 

 been found to be at the surface level ; secondly, because of the 

 presence in the diseased tissues of the seedlings of palmately 

 branched hyphse, such as have been found growing in some 

 culture media, while in diseased leaves and stems obtained from 



