146 THE MICROSCOPE. 



peculiar refrangible corpuscles which are usually spherical or spindle 

 shaped. These bodies are very unstable. So soon as the surrounding 

 fluid penetrates into the cell they swell up considerably and then 

 dissolve. Close observation has shown that prolonged treatment 

 with alcohol causes these corpuscles to become smaller and more 

 resistent. This effect is immediately produced when they are 

 treated with a watery iodine solution, and this is the best means for 

 examining them; they then appear darker or lighter yellow accord- 

 ing to the strength of the solution. Millon's reagent colors them 

 when coagulated, a brick red, and nitric acid yellow. These reac- 

 tions indicate that the bodies in question consist of albuminous sub- 

 stances." 



These corpuscles are present in the non-assimilating cells before 

 starch-grains appear at all, and when they do appear they bear the 

 same relation to the starch-corpuscles as in the assimilating cells they 

 do to the chlorophyll-corpuscles. 1 hey may be formed at the peri- 

 phery, or in any portion of the cells, and their development follows 

 the same rules as already described in the chlorophyll-corpuscle. 

 As the starch-grains reach maturity the corpuscle ccntracts and 

 disappears completely. The ofifice of these corpuscles is, apparent- 

 ly, the transformation of the superabundant nutriment elaborated 

 by the assimilating, chlorophyll furnished cells, into the more per- 

 manent form of starch. In growing or recently developed parts of 

 plants the various appearances characteristic of the several stages 

 of growth may be observed. The grains first appear as bright 

 points within the corpuscles, with growth they become .'spherical, 

 and in many cases show a marked concentric structure which at 

 maturity may determine various shapes to the grains. 



Comparing the descriptions which have been given, of the two 

 kinds of corpuscles which produce starch we are struck with their 

 similarity, especially as the chlorophyll-corpuscles are often found 

 producing starch and chlorophyll-grains in the same cell, or starch 

 even within the chlorophyll-grains (Sachs), but their close relation- 

 ship is more strongly shown by the fact that if the starch-forming- 

 corpuscles are brought into the light, the starch-grains are absorbed 

 and chlorophyll-grains take their place and a true chlorophyll-cor- 

 puscle is formed. This is admirably seen in an orchid, Fhajus 

 grandifolia. The young pseudo-bulb is produced underground, 

 and closely sheathed with several layers of leaf stems, and even for 



