246 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



way behind the punctum vegetationis. Adding together 

 the lengths of all the white exposed areas will give the 

 total increase in length of the radicle in any given time 

 and this may thus be compared with the growth of any 

 single region. 



In a root placed so as to induce a curvature the rings 

 are seen to be nearer together on the concave than on the 

 convex side. In a given experiment the distances between 

 6 successive rings Were 



on the concave side 1, *9, 1*5, "5, *8 



on the convex side 1*9, 2.1, 2, 1*5, '9 m ' m * ies P e( e y ' 



In this case and in many others also the rings were not 

 straight but wrinkled especially on the sides of the curving 

 portion shewing that the growth was not taking place at 

 the same rate all over the surfaces of these regions. This 

 is an example of irregular heterauxesis and seems to be 

 most manifest in those portions of the curving region 

 where the rapidity of growth is intermediate between 

 that on the concave and convex sides. 



There are three objections to the method described 

 above. Firstly, the rings formed may not be of the same 

 breadth. This can however be allowed for in taking any 

 measurements. 



Secondly, the number of rings formed is rarely very 

 large, six being a good average whilst growth in length 

 soon is found to take place only in the portion of the root 

 in front of the first ring, this the apical segment becoming 

 excessively elongated and soon including all the growing 

 regions. Hence if further measurements are required the 

 surface of this part of the root must be rebrowned by 

 immersing it in the Permanganate solution once more. 



Thirdly, the action of the Permanganate is to kill the 

 outer layers of the root, this of course being a serious 

 objection. On the other hand it must be remembered 



