338 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



experience and usually of simple microscopic jirocediire. Witli tlie arrowToots one has 

 not to deal with a single kind of starch but with a number of kinds from many different 

 botanical sources. The commercial term "arrowroot" long since lost its original signifi- 

 cance in so far as it applies to the derivation of the starch from Maranta arundinacea or 

 its varieties and forms or closely allied species. The supposed especial dietetic value of this 

 form of starch reported by Hughes in 1751 naturally brought arrowroot into prominence as 

 a peculiarly valuable form of food, since which time a number of so-called, or false, arrow- 

 roots obtained from a most diverse variety of plants have been introduced into trade. 

 In another part of this report (Part II, The Starches of Marantacew) it is pointed out 

 that the arrowroots of commerce are derived from species, varieties, and agricultural forms 

 which represent twelve families, seven orders, and three classes. It will be observed from 

 the results of this research that the recognition of the source of the arrowroot, true or false, 

 by means of the methods employed is a simple matter. 



In many technical pursuits the employment of starch enters, to a more or less important 

 degree, into various operations, particularly those of certain textile industries. Especial 

 reference was made on pages 176 and 177 to the differences in the characters of starch-pastes 

 and pseudo-solutions obtained from starches of different kinds, and to the notable varia- 

 tions in penetrability and stiffening strength exhibited by boiled starches from different 

 plant sources when prepared under the same conditions. From the records of this investi- 

 gation it is manifest that these properties, which are of such importance in the manu- 

 facture of many fabrics and in laundering, are variable to marked degrees in different 

 starches, so that a given starch may be entirely satisfactory for a certain purpose whereas 

 another may be very poor or almost if not entirely useless. Applications of the results 

 of this investigation to such conditions are strikingly apparent. For instance, if a starch 

 from a given species be found somewhat deficient in stiffening strength, such deficiency 

 may be absent from the starch of another species, variety, form, or hybrid of the same 

 genus. Moreover, as the starches of the parents are represented in the hybrid in modified 

 form it would seem obvious that desirable properties are obtainable by intelligent experi- 

 mentation along the lines carried out by the plant-breeder. Inasmuch, however, as a 

 form of starch that is lacking in certain properties that may be essential in certain textile 

 industries or in the arts may likely be rendered into a suitable state by simple and inexpen- 

 sive procedures, as instanced in the method of Bellmas (page 176), the kind of starch will 

 in all probability be found to be of insignificance in comparison with the cost of the raw 

 material. Nevertheless, the principles underlying the natural protluction of special forms 

 of starch by cultivation, selection, in-breeding, cross-breeding, and hybridization have a 

 broad applicabilitj^ in connection with many plant products which have a wide economic 

 value, especially as regards medicinal substances, notwithstanding the very important 

 production of the latter synthetically during very recent years. 



APPLICATIONS OF PRINCIPLES TO PHARMACODYNAMICS. 



The cultivation of medicinal plants, which as yet has been carried on to but a very 

 limited extent, has shown that in the case of certain members of Ritbiacecc and Enjthroxy- 

 laccw cultivation has increased the yield of medicinal substances, whereas in other plants, 

 especially those of Solanacece, the change from the wild to the cultivated state has had the 

 opposite effect. The author is not familiar with any instance where an attempt has been 

 made to qualitatively modify medicinal substances by any of the methods in use by the 

 plant-breeder, but there are many known cases where certain toxic properties common to 

 a genus are modified both cjuantitatively and qualitati\-ely in the difTerent members of 

 the genus. To what extent the qualitative variations are to be attributed to different 

 proportions of the active constituents or to stereoisomeric modifications is as yet wholly 

 speculative. It would seem, however, inasmuch as the various gross characteristics of 



