178 
Notes on Recent LiteraUire. 
Conclusion. 
In looking back upon the preceding summary—in which it is 
believed that most of the relevant botanical literature of the subject 
has been noticed, though doubtless some work on the zoological 
side has been overlooked—it is fairly obvious that at present there 
is some difficulty in arriving at any safe generalisations or conclusions 
regarding the nature of the various bodies to which the term 
chondriosome has been applied by different writers. It is equally 
obvious that a sharp distinction must be drawn between chromidial 
bodies which arise by extrusion of chromatin from the nucleus, 
assuming that the observations of the actual extrusion of such 
bodies are correct, and the various other bodies which have been 
shown to have no such genetic relation to the nucleus. The evidence 
as to the existence of true chromidia in plants is somewhat scanty 
and unconvincing, for while it can hardly be doubted that portions 
of nuclear chromatin may pass into the cytoplasm from nuclei 
undergoing degeneration, as in the tapetum cells of pollen-sacs, 
it is doubtful whether these have anything in common with the 
typical chromidia of certain Protozoa. Goldschmidt’s view that 
chromidia of nuclear origin are of widespread occurrence in animal 
tissues need not be further discussed here, since we are mainly 
concerned with vegetable cytology, but it may be noted that even 
in the Protozoa there is evidence of the existence of chondriosome- 
like bodies of non-nuclear origin. 
When we take into consideration the various statements made 
regarding the nature and function of the bodies of non-nuclear 
origin which have been described in plant cells and which have 
been collectively termed chondriosomes, it must be admitted that 
at present the literature of the subject raises many questions while 
it can hardly be said to have definitely solved any. It remains for 
future work to show whether the chondriosomes of plants (and 
animals) are actually sui generis cell-organs which like the nucleus 
itself persist from generation to generation—in which case they 
might well possess the important role in heredity assigned to them 
by Meves; whether they are on the other hand merely artefacts in 
the sense of being myelin or emulsion forms produced by the action 
of emulsifying reagents upon fatty or lipoid substances, or (in plants 
possessing chromatophores) leucoplasts deformed by the action of 
fixative reagents ; whether their function, or one of their functions, 
in plants is to give rise to chromatophores; and so on. 
Whether or not the data already accumulated regarding these 
bodies be regarded as sufficient for the formation of any definite 
conclusions on these and various other points, there can be no 
doubt that the observations and theories here summarised have 
raised or brought into prominence many interesting problems, 
besides introducing improved methods of microtechnical investigation 
and opening up new fields for further work in vegetable cytology 
and physiology. 
