GENUS TACCA. 687 



ing in water until the grains are fully gelatinized, the solution and some of the grains are colored 

 deeply with iodine, but some of the grains do not react. The gelatinized grains are smooth and 

 rounded and somewhat lobulated at one end. If excess of iodine be added, the grains which pre- 

 viously had not reacted exhibit voilet-colored capsules. 



Staining Reactions. With gentian violet reaction begins in 3 minutes, but after 30 minutes 

 the grains are only lightly stained. 



With safranin reaction begins in 2 minutes, but after 30 minutes the grains are lightly stained. 



Temperature Reaction. The temperature of gelatinization is 62 to 64 C, mean 63. 



Effects of Various Reagents. With chloral hydrate-iodine the reaction begins slightly in 1^ 

 minutes, and is complete in four-fifths in 20 minutes. The reaction is incomplete in an hour. The 

 hilum becomes very distinct as a dark spot or bubble, but the lamellte disappear. The angles of 

 the facets become dark, and gelatinization begins at these parts without much swelling and spreads 

 up over the whole grain. Later, the lines of junction of the facets and the angles swell out more 

 than the rest of the grain so that the facets appear to be concave. Rarely there is swelling at both 

 ends. Those grains which swell slowly often show an irregular swelling or protrusion of the whole 

 margin surrounding a central ungelatinized portion, which latter finally becomes gelatinized. The 

 gelatinized grains have a dark blue marginal ring, inclosing a lighter space which represents the 

 altered hilum. 



Reaction with chromic acid begins in 30 seconds and is over in 3J^ minutes. The hilum is 

 distinct, but the lamelliE are not more so than in the normal grain. The body of the grain becomes 

 marked throughout by fine striae radiating from the hilum. The hilum swells in common with 

 other central parts of the grain, pushing the substance of the grain out to the margin, which is 

 comparatively thick and finely striated, but without refractive bands. The margin becomes thinner 

 and clearer and finally dissolves at one point; the contents flow out and gradually disappear, the 

 capsule then dissolves, the portion opposite the point where the dissolution first occurred disappear- 

 ing last. 



With pyrogallic acid the reaction begins in 30 seconds and is over in 33^ minutes. The hilum 

 is distinct as a dark bubble, but the lamellse are not especially distinct. The hilum swells upward 

 greatly, the substance of the body of grain in the meantime becoming divided by fine striae. 

 The inner part is transformed into a gelatinous mass, and the more resistant outer part forms a 

 thick, finely striated ring which gradually becomes thinner and clearer, and a large gelatinized 

 grain is formed, which is much crumpled and folded, particularly at the faceted end. The edges 

 of the facets may swell out more than the rest of the grain. The swollen grains retain but little of 

 the original form. 



The reaction with ferric chloride begins in some grains in 2}4 minutes and is over in 35 minutes. 

 The hilum becomes distinct as a dark bubble, but the lamellae disappear. The marginal part of 

 the grain becomes clearer and darker, the inner portion appearing light and opaque. Gelatinization 

 with some irregular lobular protrusion begins from the corners and lines of junction of the facets. 

 The hilum swells greatly before this process has gone very far, and some of the substance of the grain 

 moves marginally, the margin appearing finely striated. The margin finally clears and a gelatinized 

 grain is formed. The grains are large, clear, and much lobulated and distorted. 



Reaction with Purdy's solution begins in 2J^ minutes. About half are fully swollen and most 

 of the remaining half are not affected after an hour. The hilum becomes very distinct as a dark 

 spot or bubble. The lamelhe are also very distinct. The hilum swells rapidly, the body of the grain, 

 which previously had been divided by fine striae, is pushed out to form a distinct, broad ring which 

 shows finely striated, refractive, and non-refractive bands. This ring gradually clears. The swollen 

 grains are large and clear, and are not much crumpled or distorted. 



