FORM AND SIZE OF PARTICLES EMPLOYED IN CONSTRUCTION OF PLANTS. 569 



scope is not always indicative of the crystalline nature of micellce. The striation 

 is brought about by dissimilar chemical constitution and unequal quantities of 

 water in the successive strata of molecular groups, and may be present, equally 

 well, where the groups of molecules do not possess crystalline form. Moreover, 

 the results which have been obtained by the so-called carbonization or pulveriza- 

 tion of the cell-walls goes against tlie assumption of crystal-like micelliB. By 

 treating with sulphuric acid, heating up to 60°-70°C., and then operating with 

 hydrochloric acid, the cell-wall is broken up into extraordinarily small fragments, 

 exhibiting parallel strise and frequent clefts; and these often subdivided into short, 

 veiy line filaments, which filaments break up by pressure into granules imbedded 

 in a homogeneous gelatinous matrix. A definite geometrical crystalline form 

 cannot be demonstrated in this ground-substance. Moreover, the granules are not 

 bounded by plane surfaces and rectilineal edges, and have no resemblance to the 

 smallest visible portions of crystals. All the observations obtained by this class 

 of experiment tend rather to show that the granules are grouped into filaments, 

 or lamelliB, or both, that they are joined together by extremely delicate proto- 

 plasmic threads, and that the cell-wall possesses a reticular structure. If these 

 granules and filaments are not themselves the micellae, but groupings, rather, of a 

 higher order, still their outlines in no case suggest the forms of crystalline micellae. 

 The idea that the micellfe possess a reticular form was corrected much earlier. If 

 the same rule which prevails in the grouping of the molecules into micellae would 

 also hold in the association of micellae into groups of high order, and ultimately 

 into bodies which are in their outline recognizable by our senses, then one might 

 hope to dei'ive the form of the micellae, and even the form of the molecules 

 themselves, from the form of the smallest visible portions of the plant. This 

 supposition would lead to the conception of reticular micellae and reticular mole- 

 cules in the organized parts of plants. It is, however, very noticeable that all 

 researches concerning the form of the smallest visible elements of protoplasm point 

 to a reticular structure. In the dry coating of the so-called plasmodia of myxo- 

 mycetes, which contains no cellulose, but consists of protoplasm (in which ai-e 

 deposited crystals of calcium oxalate), for example, in the plasmodium of Leocarpus 

 fragilis, it is seen that the entire papery skin consists of twisted threads extend- 

 ing in all directions, which anastomose in a reticular manner, and that the meshes 

 of this net-work are filled with a highly refringent substance. 



In the hyaline ectoplasm of the living protoplasm which inhabit the cell- 

 ehamber, veiy fine threads have been observed lying side by side, and if this 

 protoplasm is displaced and killed by alcohol, it can be ascertained by the aid of 

 colouring matters that the whole cell-body is built up of very minute threads 

 connected into a net-work, and that the meshes of this fine net-work are filled with 

 a fluid substance. Within the threads are to be seen, however, corpuscles arranged 

 in rows, which have received the name of microsomata. 



The whole protoplasmic cell-body, including the cell-nucleus, appears generally 

 to possess this same structure, for in the processes which lead up to the division 



