58 Acton . — On the formation of sugars 
of a young flower bud, before the gland-cells have reached 
their full size, be examined under a high power, the proto- 
plasm of the epithelium and epithem-tissue appear as shown 
in Figs. 3 and 4. 
The cells are completely filled with protoplasm having no 
vacuoles; they contain a large conspicuous clearly-defined 
nucleus, and numerous small roundish or irregularly-shaped 
granules of a proteid nature ; the proof that these granules 
are of a proteid and not carbohydrate or resinous constitution 
is given in full below. At this stage the cells contain no 
sugar or substances which reduce Fehling’s solution even 
after treatment with dilute acid to ‘invert’ 1 any saccharons 
which might be present. 
These observations may be made on sections mounted in 
dilute glycerin or glycerin and alcohol, but are much more 
easily observed when the sections are stained with borax- 
carmine or Hoffmann’s blue, especially if the latter be used 
dilute so as to colour the protoplasm only and not also the 
cell-wall. Haematoxylin and ammonia-carmine also show 
the structure well if used dilute. 
In the older buds, where the gland-cells have reached their 
maximum development, but still some time before the 
opening of the flower, small vacuoles can be observed in the 
protoplasm, and the number of granules rapidly diminishes 
with the advancing age of the cells. At this stage small 
quantities of sugar can be detected in the cells by the Fehling 
test ; an immediate red precipitate of cuprous oxide is ob- 
tained on dipping the sections in the boiling reagent, which 
shows that glucose is present ; but the precipitate is markedly 
more copious if the sections are allowed to remain for some 
time in the reagent, or are previously treated with dilute 
acid, to cause inversion of any saccharons, showing that 
saccharon is present in addition to glucose. 
In the next stages the vacuoles rapidly enlarge, the granules 
1 See Roscoe and Schorlemmer, Treatise on Chemistry, vol. iii, pt. ii, ‘ Cane 
sugar,’ London, 1884 ; and Armstrong and Groves, loc. cit. 
