Feb. 26, 1885] 



NA TURE 



39 ! 



investigators of plant histology : Prof. Russow. The 

 subject is that of the existence of intercellular protoplasm. 



Dr. Schaarschmidt has already given the literature. The 

 only other observation with which I am acquainted is that 

 of Prof. Frommann ("Zur Lehre von der Bildung der 

 Membran von Pflanzenzellen" — separate pamphlet) who 

 finds in the intercellular spaces of the young stem of 

 Ricinus communis, protoplasm ; starch grains, and chloro- 

 phyll grains. 



The observations as to the existence of intercellular 

 protoplasm depend chiefly upon the staining reactions of 

 iodine and sulphuric acid or chlor. zinc. iod. The cell 

 wall turns blue, or remains yellow as the case may be : the 

 protoplasm, and in certain cases a substance ; in or lining 

 the intercellular spaces, stains dark brown. ( r again in 

 some instances — e.g., the rhizome of A spidium filix mas — 

 the substance in the intercellular space remains uncoloured. 

 Other observers have employed other staining reagents 

 after swelling with sulphuric acid and chlor. zinc. iod. — e.g., 

 saffranin, eosin, or anilin blue — and in this case a colour- 

 ation is observed of the protoplasm on the one hand and 

 of the intercellular space substance on the other. 



Dealing first with the iodine and sulphuric acid or chlor. 

 zinc. iod. method, it is obvious that, besides the protoplasm 

 which assumes the well-known dark brown colouration, 

 any lignified, cuticularised or suberised membranes would 

 react in the same way, and in the case of one of Berthold's 

 d. Deut. Bot. Gesell.) examples, e.g., young stem of 

 Ligustrum vulgare, the substance which so markedly 

 stains, does actually consist of the external membrane of 

 the intercellular space, which towards the free surface has 

 undergone changes associated with partial lignification 

 (Gardiner, Proc. Camb. Phil. Soc, Nov. 10th, 18841, as 

 can be readily proved by treating a section with aniline 

 chloride and hydrochloric acid, when the well-known gold 

 yellow reaction of lignified tissue appears. In the same 

 way the substance which does not stain with iodine and 

 sulphuric acid might be of a mucilaginous nature, and 

 like the mucilage of the external portions of the wall of 

 the seed of Ceratonia siliqua give the same reaction, viz., 

 remain uncoloured. But there are cases which are not so 

 easy to deal with, as I have stated elsewhere {Proc. 

 Cam!: Phil. Soc, Feb. nth, 1884), I found that the 

 Hofmann's blue which I had so successfully employed for 

 demonstrating the existence of protoplasmic filaments in 

 the pit-closing-membrane stained not only protoplasm but 

 also certain forms of mucilage. Like Russow {Sitzber. d. 

 Dorp.tt. Nat'urfor., Sept., 1SS3), I thought at first that 

 in Aucuba Japonica I had discovered the existence of 

 intercellular protoplasm, but I observed later on that this 

 staining substance could be seen to arise as drops on the 

 external walls and that these drops went blue with iodine : 

 thus demonstrating that they were not protoplasm but 

 mucilage. I therefore made experiments with the methy- 

 lene blue which I had found {Phil. Trans., part iii., 18S3) 

 to be so useful as a stain for the cell wall, and so 

 differentiating in its action. (A solution is made in water 

 containing a trace of alcohol ; the solution being diluted 

 with water before use. The section freed from alcohol by 

 repeated washing, is left to stain for about 20 seconds, 

 washed and mounted in water). I further found that 

 methylene blue stains equally well, all substances formed 

 by the degeneration of cellulose walls, such as mucilage 

 and the like. So while Hofmann's blue stains protoplasm 

 and mucilage, but not cell wall, methylene blue stains cell- 

 wall and mucilage but not protoplasm. Thus the cell- wall 

 and protoplasm may be readily discriminated in a very 

 satisfactory manner, and without this reaction it would 

 indeed be hard to distinguish the two. Many dyes behave 

 like Hofmann's blue so far as the staining of the mucilage 

 is concerned, and I have little doubt but that eosin re- 

 sembles it in this respect, though not such a good 

 differentiating stain for the protoplasm. In the course of 

 all my experiments, which I have repeated several times, 



I have never found intercellular protoplasm but often 

 intercellular mucilage. In all cortex tissues which 

 are often remarkable for their mucilaginous character 

 — ^\; r ., Viscum, Fraxinus, Ilex — mucilaginous degene- 

 ration of the free cell-walls very usually occurs, which 

 often — e.g., Ilex, Viscum — extends even to the whole 

 middle lamella. \\\Aspidhtm filix-mas, Blechnum Brazili- 

 ense and other ferns, theso-called cuticularised threads 

 (cuticularfaden) are in reality rods consisting mainly of 

 mucilage which arise as drops on the free surface of the 

 cell-wall and increase in length by repeated basipetal 

 formation. I do not therefore find myself able to allow of 

 the existence of intercellular protoplasm. 



As to the middle lamella being protoplasm I can only 

 refer to the statements I made with regard to Frommann 

 and Elsberg's researches {Quart. Jour. Mic. Sci., March, 

 1883) and I share fully in the opinion of Prof. Russow 

 (" Ueber die Auskleidung der Intercellularen," Sitzber. d. 

 Dnrpal. Naturjor., August, 1S84) that if such were the 

 case it is clear that we could have no such thing as a mass of 

 tissue resisting great stress. The cells cannot be connected 

 together by protoplasm. As to the existence of the inter- 

 cellular chlorophyll grains of which Dr. Schaarschmidt 

 speaks, and the chlorophyll grains and starch grains 

 observed by Prof. Frommann, I also share Prof. Russow's 

 view {loc. oit.) that the above investigators must have been 

 deceived by some abnormal appearance, for what could be 

 the physiological significance of such a phenomenon ? The 

 full details of my researches on the subject will, I hope, 

 shortly appear in the On irterly Journal of Microscopical 

 Science. Walter Gardiner 



Botanical Laboratory, Cambridge, February 10 



THE BANGOR LABORATORIES 



THE following is a description of the Laboratories of 

 University College, Bangor, which were opened by 

 Sir William Thomson on the 2nd inst. The illustration 

 shows the ground floor arrangement ; in the upper floor 

 are a magnetism-room and an optical gallery. 



The new physical and chemical laboratories occupy 

 the site of the old stables and coach-houses of the 

 " Penrhyn Anns Hotel," which is now used as the main 

 building of the College ; and, to lessen expense, a plan 

 has been adopted by which the old walls are, as far as 

 possible, taken advantage of for outside walls and par- 

 titions. To utilise the available space to the utmost it 

 was decided to roof in the whole area, which measures 

 about 120 feet by 80 feet. This area is bounded on the 

 east by the main building of the College ; on the south by a 

 private road which runs nearly parallel to the Shrewsbury 

 and Holyhead turnpike road, and gradually ascends until 

 opposite the laboratories, the ground is about 20 feet 

 above the level of the turnpike ; on the west and north by 

 the private grounds of the College. 



At the extreme east end of the south front of the 

 laboratory buildings is a wide door opening into a vesti- 

 bule, from which a passage leads north, and terminates 

 in a wider space or hall. From this hall a long corridor 

 runs parallel to the south front, dividing the floor space 

 into two nearly equal parts. Of these the southern is set 

 apart for physics, the northern for chemistry. 



The physical and chemical lecture-theatres (23,41) are of 

 the same size, 32 feet square and 19 feet high, and are placed 

 side by side with the corridor as a separating space be- 

 tween them. The internal arrangements are nearly the 

 same in both rooms. The students' entrances are oppo- 

 site one another in the corridor. The benches, eight in 

 number, rise from the front to the back of the room, and 

 front toward the west. The lecture-tables are placed 

 about 4 feet from the front bench, and between each 

 table and the west wall there is a clear space between 

 7 and 8 feet wide. In the physical lecture-theatre the 

 table is supported on four pillars of masonry, and is en- 



