797 
‘ Heterotypical Reduction 7 in Somatic Cells. 
This was the case after immersion for \ hour, and after more prolonged 
immersion these features were more pronounced. With this strength of 
solution a very marked ‘ heterotypical * character was seen in the chromo¬ 
somes, but there appeared to be less characteristic action of the poison upon 
the tissue, and fewer structural abnormalities resulted from it. With a 
o*5 / solution of chloral hydrate on the other hand, much better effects were 
obtained, but prolonged immersion proved necessary in order to get the 
characteristic action of the drug at all marked. Very little shrinkage and 
distortion were seen with this percentage. The heterotypical appearance of 
the chromosomes was also less marked. The point of importance in these 
results consisted in the apparent possibility of modifying the degree of the 
heterotypical character of the chromosomes. 
Summary of the Results obtained in the Roots of 
Pisum SATIVUM. 
It is evident, from the results described above, that in the pea, as in 
Galtonia and the bean, the gross effect of the action of the chloral hydrate 
upon the root tissue consists in the disappearance of the achromatic fibres and 
consequent production of tetraploid cells. At the earlier stages of fixation 
there is the same arrest of the movement of the split chromosomes to the 
poles, and re-fusion to form one mass; later, the same growth to unusual 
size of the cells containing such masses ; and finally, the same multipolar 
division or degeneration of the abnormally large nuclei, both the latter 
processes being very well shown. 
The point of particular interest in the pea, however, lies in the occurrence 
of Nemec’s ‘heterotypical ’ figures, which may now be discussed at length. 
These figures are very striking (Figs. 23 and 26), and occur not only in 
roots fixed after a period of growth subsequent to immersion in the chloral 
hydrate, but also in those fixed directly after removal from the latter. 
After an interval of twenty-two hours the majority of division figures seem 
either to consist entirely of such ‘ heterotypical ’ chromosomes, or to contain 
a certain number of them scattered amongst others more normal in shape. 
They are seen after forty-four hours’ subsequent growth, and also at sixty 
hours, but at these later stages there are fewer of pronounced heterotypical 
appearance, many showing a character intermediate between this and that 
of the normal pea chromosome. 
Since, then, the occurrence of the heterotypical figures cannot be 
doubted, the question resolves itself into that of determining whether they 
really arise in connexion with the process of reduction, and are comparable 
to those seen in reproductive tissue, or whether their shape is caused by 
some process of a different nature. 
The evidence in favour of their being true reduction-figures is as 
follows:— 
