6 9 
Beer. — On Elaioplasts. 
I have kept the young capitula in total darkness for several ( 3 - 6 ) days 
without altering the development or structure of the elaioplasts of the corolla- 
hairs in the least. 
The only deviation which I have ever found in the behaviour of the 
plastids of the corolla-hairs occurred in a very young capitulum from which 
the protecting bracts had been dissected away so that the tiny flower-buds 
were exposed to the full effect of the light. 
Here the aggregation of the plastids into elaioplasts had been retarded 
in a number of cells. 
The clumping together of the plastids of a cell into a more or less close 
mass is by no means an unusual occurrence. Kraus (12) many years ago 
described the effect of cold upon the chlorophyll-grains of winter leaves. Here 
these bodies were found to have passed from the walls to the interior of the 
cells and were there aggregated in clumps. Charles Darwin ( 13 ), in 1882, 
observed a very close massing of the chloroplasts in the cells of certain 
insectivorous plants under the influence of ammonium carbonate (a solution 
of 4-7 parts of ammonium carbonate in 1,000 parts water). 
The work of Stahl ( 14 ), as well as of others, has shown that an irregular 
aggregation of chloroplasts is produced under the influence of intense 
illumination. 
Pfefifer ( 15 ) mentions that similar results are induced by injuries and 
various mechanical agencies. 
The close massing of the plastids into compact elaioplasts is most 
probably connected with their degeneration, and may very likely be com- 
pared to the aggregation of these bodies produced by the injurious agencies 
enumerated above. That the elaioplasts have any particular function to 
perform which is of direct significance to the life of the cell is most unlikely. 
A secondary use for the degeneration products of the plastids — massed 
into elaioplasts — certainly does occur in the case of the corolla-hairs of 
Gaillardia , for here they give rise to the yellow pigment which forms an 
important part of the attractive apparatus of the mature flower. 
In other situations, however, the elaioplasts seem to disappear, without 
having even this secondary biological significance. 
It will be interesting to examine the Monocotyledonous elaioplasts 
again more closely in the light of what has been learnt of these bodies in 
Gaillardia , to see whether they possess the same nature and history. 
I hope to obtain material for this purpose during the next season. 
In conclusion, I must express my indebtedness to a Government grant 
for assistance in carrying out this research. 
