PHAIUS. 



743 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 95 per 

 cent of the entire number of grains and 98 per cent of 

 the total starch in 15 seconds; complete gelatinization of 

 all grains occurs in 30 seconds. (Chart D 580.) 



The hiluin becomes more distinct than in P. grandi- 

 folius, and the lamellae also appear more distinct, but 

 do not remain visible during the greater part of the 

 reaction as in P. grandifolius. A refractive band about 

 the margin is not usually to be distinguished owing to 

 the rapidity of the reaction. Gelatinization begins at the 

 proximal end and this is occasionally but not usually 

 followed by gelatinization at the corners of the distal 

 margin. The hilum enlarges very greatly and very 

 rapidly and pushes out the proximal end of the grain. 

 Two widely branching fissures run rapidly from the 

 liilum, just inside the margin, to the distal end and these 

 divide the starch between the hilum and the distal end 

 into many rather coarse, irregularly placed granules, and 

 a gelatinization and swelling of the grain proceed dis- 

 talwards from the proximal end, this part of the grain 

 opening out fan-wise with considerable infolding and 

 invagination of the capsule at different points. In many 

 grains a granular appearance persists here for a con- 

 siderable time after gelatinization is complete in the 

 rest of the grain. The gelatinized grains are larger and 

 thinner-walled than in P. grandifolius, but somewhat less 

 distorted than in that starch. 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 58 per 

 cent of the entire number of grains and 90 per cent of 

 the total starch in 5 minutes; in about 83 per cent of 

 the grains and 95 per cent of the total starch in 15 min- 

 utes ; in about 92 per cent of the grains and 98 per cent 

 of the total starch in 30 minutes; in about 95 per cent 

 of the grains and 99 per cent of the total starch in 45 min- 

 utes ; in about 99 per cent of the grains and over 99 per 

 cent of the total starch in 60 minutes. (Chart D 581.) 



A bubble appears less frequently at the hilum than in 

 P. grandifolius and the beginning of gelatinization with 

 distention of the capsule at the proximal end was not 

 observed. The process follows the course more frequently 

 found in P. grandifolius, but there it is accompanied 

 with more general distortion and elongation of the proxi- 

 mal end of many grains. The lamella? are not so sharply 

 defined and their definition is much more quickly lost. 

 The 2 fissures which leave the hilum may be at first clean- 

 cut, but they very soon become much branched and plume- 

 like; in the narrower grains a large, single, plume-like 

 fissure may be found; the fissures are much more com- 

 monly diffusely branched than in P. grandifolius. The 

 mesial region is usually disorganized with the appear- 

 ance of less refractive granules, and the lamella? near the 

 distal margin, as well as in the marginal band at the 

 proximal end and sides, are less frequently broken down 

 into linear granules than in P. grandifolius. This mar- 

 ginal band at the proximal end and sides is usually not 

 so broad nor so resistant as in P. grandifolius; even in 

 grains resembling this species in form and with a moder- 

 ately broad border, this band usually becomes undulating 

 and gelatinized without breaking into granules. 



The gelatinized grains are swollen and distorted, the 

 latter more throughout the entire margin of the grain; 



the majority of grains are elongated and often undulat- 

 ing at the proximal end, and rarely depressed as found 

 moderately often in P. grandifolius. A group of refrac- 

 tive granules appears at the hilum with less frequency, 

 since they are much less resistant than in P. grandifolius. 

 The gelatinized grains do not resemble the form of the 

 untreated grain as in P. grandifolius. 



The reaction with potassium sulphocyanate begins 

 immediately. Complete gelatinization occurs in about 

 93 per cent of the entire number of grains and over 99 

 per cent of the total starch in 5 minutes; in about 98 per 

 cent of the grains and over 99 per cent of the total starch 

 in 10 minutes; in about 99 per cent of the grains and 

 over 99 per cent of the total starch in 15 minutes. (Chart 

 D 582.) 



The hilum swells as noted in P. grandifolius, but the 

 lamellae do not become nearly so sharply defined. Two 

 plume-like fissures usually proceed obliquely from the 

 hilum to the distal end, and sometimes an additional 

 median, branched fissure or a group of median fissures 

 appear in broader grains; definite fissures with the 

 exception of those between lateral border and mesial 

 portion are usually absent in P. grandifolius. The 

 mesial portion is generally broken down into much less 

 refractive granules, and the group of granules around 

 the hilum is much less frequent than in P. grandifolius. 

 The border at the middle of the distal margin is fre- 

 quently the most resistant part, instead of at the proxi- 

 mal end, as noted for P. grandifolius, but the distal 

 corners are much less resistant and are gelatinized with 

 more distortion than in P. grandifoliits. The gelatinized 

 grains are more distorted, especially at the proximal 

 end than in P. grandifolius; they, as in that species, do 

 not resemble the shape of the untreated grain. 



The reaction with potassium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 93 per 

 cent of the grains and over 99 per cent of the total starch 

 in 2 minutes; in about 99 per cent of both the grains 

 and total starch in 5 minutes. (Chart D 583.) 



The reaction is so rapid that the minute steps can not 

 be satisfactorily determined as in P. grandifolius. The 

 gelatinized grains are much swollen and distorted; less 

 frequently evenly telescoped at the distal margin than 

 in P. grandifolius, the distal corners at least being 

 thrown into convolutions. The entire grain is rarely 

 telescoped, with concave invagination at the proximal 

 end, as found moderately often in P. grandifolius. The 

 wall of the gelatinized grain, especially at the proximal 

 end, when not distorted at this point is thinner than in 

 P. grandifolius. The gelatinized grains do not resem- 

 ble the form of the untreated grain as in P. grandifolius. 



The reaction with sodium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 70 per 

 cent of the entire number of grains and 92 per cent of the 

 total starch in 2 minutes; in about 85 per cent of the 

 grains and 97 per cent of the total starch in 5 minutes ; 

 in about 98 per cent of the grains and over 99 per cent 

 of the total starch in 15 minutes. (Chart D 584.) 



A bubble is sometimes detected, more frequently than 

 in P. grandifolius; it reacts in the same manner as noted 

 in that species. The lamella? become more sharply de- 

 fined, but the definition is not so sharp as in P. grandi- 

 folius. Two fissures which branch profusely, especially 

 in the region of the distal corners, are usually formed, 



