7 8i 
4 Heterotypical Reduction' in Somatic Cells. 
of the processes concerned. It will be best, therefore, to describe in detail 
typical experiments on the three plants— Galtonia , bean, and pea, and then 
to discuss the evidence obtained as to the nature of the ‘ heterotypical ’ 
figures. 
Hyacinthus candicans. 
In working with Galtonia , the bulbs were grown over water in ordinary 
hyacinth glasses, and the experiments carried out as described above. 
After immersion of their roots in the solution of chloral hydrate, the bulbs 
were replaced over water, and fixations were made after varying periods of 
further growth. The periods examined were 3, 5, 16, 20, 40, 68, and 
7ohrs., but owing to the occurrence of certain periods of diminished nuclear 
activity, caused by the drug, some of these fixations presented practically 
the same features as those preceding them. The roots which afforded most 
information as to the action of the poison were those fixed at intervals of 
about 5, 20, and 40 hrs. after replacement over water. Numerous series of 
experiments were performed upon the root tissue of Galtonia for the reason 
that, owing to the large size of its cells and to its general clearness, it affords 
good figures for counting and comparing the chromosome number in the 
normal and pathological cells. It was found that the results of the various 
series were the same in general character, although some minor points 
of difference were frequently noticeable between two corresponding fixations 
in two experiments. This was owing, no doubt, to differences between 
individual roots, or between the conditions under which the experiments had 
been performed, such for instance as slight dissimilarities of temperature 
and light. In making a microscopical examination of the tissues which had 
been subjected to experiment, two different kinds of effect were observed ; 
namely, the general action of the chloral hydrate upon the entire tissue, 
affecting nuclei, cytoplasm, and cell walls ; and the peculiar structural 
alterations arising secondarily. The first effect passed off more or less 
completely, unless the experiment had been of a very severe character, and 
the tissue as a whole resumed its normal appearance. The second effect, on 
the contrary, was of a more permanent nature, and tended to persist unless 
eradicated by some activity of the tissue. This second effect also afforded, 
at the later periods of the experiment, the only data available for tracing 
the action of the chloral hydrate upon the root. 
In the experiment on Galtonia selected for description the roots were 
fixed:— 
1. After 1 hr. in 075 % chloral hydrate, 
2. „ 1 hours washing in tap-water, 
3. „ 5 hours’ subsequent growth over water, 
4* >5 » >j >» >> » 
6* 5) 44 >> 5» >> ’> 
and therefore show the effect of the poison continuing over a considerable 
