SCIENCE- G OS SIP. 



279 



•contribution unnoted, leaving the different slides 

 to commend themselves to their observers, if for 

 nothing else than for the elegance of form which 

 they present. — W. Pumphrey. 



It is evident that Mr. Pumphrey has lost sight 

 of a very important factor in the P.M.S.— namely, 

 the giving out of information which, however 

 "trite" it may be to the senior members, is a 

 necessity if the success of the Society is to be 

 maintained. We must cater for the learners as 

 well ; and however excellent may be the dealer's 

 .slides which are at times furnished by members, 

 they do not advance the best interests of the 

 P.M.S. as slides of less perfect finish do, whose 

 bona-fide touches and descriptions are instinct 

 with the spirit of mutual helpfulness. Even quota- 

 tions from books such as Carpenter's might form 

 the groundwork of some interesting and practical 

 communications. "Light, heat, moisture, etc.," 

 in the formation of vegetable tissues, call up some 

 ■of the most interesting problems connected with 

 structural botany. For instance : What causes a 



/ 



Rhcinm communis (fig. 2) shows a hypocotyle of 

 this dicotyledonous plant. The vascular bundles 

 consist of phloem externally and xylem internally, 

 separated by a layer of cambium which is con- 

 tinued into the fundamental tissue lying between 



U w* L " 



Fig. 2. Section of Stem of Ricinus. 



the vascular bundles as interfascicular cambium. 

 The xylem contains vessels with narrow pits and 

 vessels with broad pits with wood parenchyma 

 between them. The pith and primary cortex are 

 also shown. 



Cyperics longus (fig. 3) shows irregular disposi- 

 tion of vascular bundles in monocotyledonous 

 stem. This arrangement of bundles is due to the 



Fig. 1. Suction - o: 



if Akistolochi.v. 



■double, or even a multiple, succession of rings to 

 occupy the place of a single one, as ascertained by 

 transverse sections of wood? — J. BvrTibedk. 



The examination of these slides has given me 

 much pleasure, but I nevertheless concur with the 

 previous writer in his remarks respecting the 

 absence of notes and the absence of any evidence 

 of individual work. These slides should not be 

 circulated merely as objects of beauty. They must 

 convey instruction. We are never tired of having 

 described to us the beautiful devices which Nature 

 adopts to build up the various natural objects that 

 surround us. There is, in truth, a very fine delight 

 in the acquisition of scientific information new to 

 ourselves, even if the information has been known 

 for ages to others ; and, further, those to whom 

 these scientific facts may be well known never tire 

 of having them brought fresh to their notice — 

 especially if the old story be well told and well 

 illustrated. I have photographed three of the 

 slides and appended notes. — J. R. L. Dixon. 



AristolooMa elematitis (fig. 1) shows the con- 

 centric and regular disposition of the vascular 

 bundles in dicotyledonous stems. It will be 

 observed that the stem is a young one, as evidenced 

 by the amount of pith, which in the root may be 

 so much checked, as almost entirely to disappear. 



\ 





Fig. 3. Section of Stem of Gyperus. 



obliquely radial course of the leaf -trace bundles 

 These enter the stem from the leaves, run obliquely 

 downwards into the stem, then bend again out- 

 wards and approach the surface. A transverse 

 section may thus pass through different leaf -trace 

 bundles at different heights in their course and 

 show therefore bundles of different structure and 

 size. — J. B,. L. Dixon. 



