‘Heterotypical Reduction' in Somatic Cells . 
793 
PlSUM SATIVUM. 
As in the case of the bean, two methods of cultivation were used 
in starting pea roots for experiment, and again the most satisfactory- 
results were obtained by that of growing them in damp sawdust. In spite 
of the fact that those started over water had the advantage of less manipu¬ 
lation, and could be poisoned and replaced on the cork without any friction 
of the root-tip, it was found to be extremely difficult to keep them free 
from mould. 
The pea proved to be the most fruitful in results of the three plants 
examined ; for not only is it particularly sensitive to the action of the 
chloral hydrate—showing a remarkable variety of abnormal figures after 
treatment with the latter, but it is also the only one in which occur the all- 
important ‘heterotypical’ figures. This is said advisedly, in spite of the 
statement made by Nemec in his most recent paper, to the effect that these 
figures occur also in the onion. In his detailed description, published 
in 1904, of the action of chloral hydrate upon the pea, the bean, and the 
onion, Nemec stated that the ‘ heterotypical ’ figures were found in the pea 
only, and since that statement has published no further data in correction 
of it. As was mentioned above, the onion was one among a number of 
plants used for preliminary examination before selecting individuals on 
which to carry out the detailed experiments. In this examination nothing 
resembling 6 heterotypical ’ figures was observed in the onion, although the 
other effects of the chloral hydrate were well marked. 
With a view to inducing modifications in the figures in question, which 
might afford data for the determination of their true nature, a considerable 
number of experiments were performed on the pea with varied strengths of 
solution and periods of immersion. 
For comparison with the results described above in Galtonia and 
the bean, however, it will be best to give first an account of an experiment 
in which pea roots were immersed for 1 hour in a 0-75 % solution of chloral 
hydrate, and to set aside for the moment the question of the nature of the 
‘ heterotypical ’ figures. 
In the experiment here described, the roots after immersion in a 075 % 
solution of the poison were fixed at the following intervals:— 
1. After 1 hour’s washing in tap water. 
2. ,, 22 hours’ subsequent growth in sawdust. 
3 * 33 45 53 3 3 33 )3 33 
4* 3) 60 33 „ 33 )3 33 
(1) After i hour's washing . 
The appearance presented by roots fixed directly after washing is 
extremely abnormal, and the tissue is so diffusely stained that it is somewhat 
