2 sy ee RS TT ¢. — = Cyr yr Vi ve We) a ge 1M AA . ; 2 A oye 28 8 ee Mh EN St a”, Nh ( ES ~ = “N ars - =“—S 5; 3 ‘Gah ta : Bus Say = - Be. ? Ag sa = sis at . a So a) 5 _~_ . Ga a En. PP oy ls Ss ee SS Na ee re ‘ ei s X = = >, Se = Wyse ye! : A a v. : i y Co pe\ ” > me : . wo 9 chen N RN es NN ran ioe Sind WE TW YY VW s Ls bo / Am 1, ® 24¢::; 4 fen | as Ay j og 5 b>) $Y 4S see : | 1 RENEE! AIA] F AVRO SUENTIAS ~ “ore yatta BP en eae) : a at a < . as a a oa rye #. fs ' } a | =). c A t dd tw 4 aes r ; : oa p i ' 4 - . U y / rs . : ‘ ’ a | 7 . b ‘ u 7 = . - s , ¥ , ’ : . i ‘ i, aa < bi) Pay = rm a ; 7 ; a . ~ ; i ae - = 4 be’ ek 3 ", J : r ‘ = - « : : « Lo - - JOURN. R. MICR.SOC. SER. Il VOL.VI. PL XI. West, Newman & C® ith. Structurek Evolution of the Floride. JOURN. R. MICR.SOC.SER. II. VOL. VI. PL. XIII. - & \ , = ‘ ~ wn 3 . F > Se 34 Bae PRS <. / a3 . ; ‘ beer F LGh™ Se , ) 4 in . y 2) AK Sy I ALKA , ~ > » ak oT Ar» SNES la My ere RE LA > Siete clad be da ded oe Se APSE DALY Lo EXT (Te EX EAP Li AD SX = ASS G Massee del. West, Newman & C® hth. Strueture& Evolution of the Floride. 20 1903 y § \ JAN JOURNAL BOTanicar OF THE ROYAL MICROSCOPICAL SOCIETY. AUGUST 1886. TRANSACTIONS OF THE SOCIETY. XI.—WNotes on the Structure and Evolution of the Floridex. By Gerorce Masses, F'.R.MLS. a (Read 14th April, 1886.) Puates XII. and XIII. Notwirustanpine the marked variety of form and structure met with in the vegetative parts of Floridex, an examination of the groups shows that there are but few types of structure, all of which can be traced back to a primitive form, illustrated by such genera as Chantransia Thur. (C. corymbifera Thur.) and Balbiania EXPLANATION OF PLATES XII. anp XIII. Fig. 1.—Trentepohlia virgatula Hary. Showing apical cells, a, d, e, also the segment or daughter-cell just after segmentation, }, f. This figure also illustrates the mode of branch formation by lateral protrusions from cells behind the apical cell; atc the first indication of a lateral branch is shown. The branches are developed in acropetal order. x 300. Fig. 2.—Porphyra laciniata Ag. Showing numerous apical cells, a, a,a,a; b, segment yet entire and watchglass-shaped. x 300, Fig. 3.—Ahnfeldtia plicata Fries. Showing the origin of the multicellular thallus to be due to peripheral or pericentral cells cut off from an axial cell; a, apical cell; +, segment. x 300. Fig. 4.—Transverse section through fig. 3 at the point c, d; axial cell a, pericentral cells b, connected by threads of protoplasm. Further back the thallus becomes thicker owing to the segmentation of the pericentral cells by radial and tangential septa. x 300. Fig. 5.—Halurus equisetifolius Kzg. Showing the apical cell a, surmounted by the uppermost whorl of branches, 6. x 300. Fig. 6.—Dasya coccinea Ag. Tlustrating the formation of branches by divisions of the apical cell; the two cells a, a, are the basal cells of new branches. If they develope equally, a dichotomy will result; 6 is the terminal cell of the podium from which the two branches a, a, originate. x 300. Fig. 7.—D. coccinea. Illustrating monopodial branching, resulting from division of the apical cell. The cells a, a’, correspond to a, a, in fig. 6, but a continued developing in the same direction as the podium, of which 4 is the uppermost cell, while the sister cell a’ grew at an angle. The cells, a’, are each connected by protoplasmic threads with three other cells. x 300. Figs. 8 & 9.—Ceramium rubrum Ag. Showing that the incurved tips of the Ser. 2.—Vou. VI. op 562 Transactions of the Society. Sirodot (= Chantransia investiens Lenor.), the latter a fresh- water species, in which the more or less branched thallus consists of single rows of superposed cells. In Hrythrotrichia Aresch., generally included in this family on account of its red colour, the structure is yet simpler, consisting of an unbranched filament of single cells placed end to end; but as the organs of reproduction branches, characteristic of this genus, are due to local growth. The upper cells are wedge-shaped, and the corticating cells a, a, first appear on the broadest end of the wedge-shaped cells, thus causing the tip to curve. At some distance behind the growing point the thin end of the wedge-shaped cells grows fastest, and the corticating branches develope all round, pushing the stem back until straight. x 300. Figs. 10 & 11.—Callithamnion polyspermum Ag. Showing the segmentation of the apical cell by oblique septa in the main axis. The segmentation of the branches is from the first by septa at right-angles to the axis of growth. x 300. Fig. 12.—Polysiphonia fastigiata Grey. Section of axial cells, showing portions of protoplasm 5, b, imprisoned between the primary layer a, a, and the secondary layers c, c, c, c, of the cell-wall; d, d, protoplasm of cells. x 600. Fig. 13.—Polysiphonia urceolata Grey. Surface view, illustrating the type of stem composed of fascicles of cells of equal length. x 250. Fig. 14.—Transverse section of fig. 13, through a, b, showing the axial and four pericentral cells. x 250. Fig. 15.—Ceramium rubrum, Germinating spore, showing origin of adpressed corticating branches a,a. xX 300. Fig. 16.—Ceramium flabelligerum J. Ag. Surface view, showing corticating branches a,a; 0, b, axial cells. x 250. Fig. 17.—Batrachospermum moniliforme Roth, Showing the basal portions of two whorls of branches, which originate from the anterior end of axial cells a, a; b, b, free branches of whorls, the corticating branches are shown at c,c. The portion represented is near the tip of the stem, and the adpressed branches are as yet short, and few in number. x 3800. Fig. 18.—Gloiosiphonia capillaris Carm. Vertical section, illustrating the type of thallus composed of agglutinated branches. The axial cells are seen at a, giving off whorls of branches at d, d, which become densely branched, and at the tips composed of minute cells forming the “cortex” 6. Some of the secondary branches do not grow towards the circumference, but parallel to the axis, as shown aticyc. xX 200: Fig. 19.—Transverse section of fig. 18, through one of the whorls of branches ; lettering same as in previous fig. x 250. Fig. 20.—Lenormandia linearis Harv. Illustrating the development of a flattened thallus from the cylindrical Polysiphonia type, due to local growth. In the apical region the section is circular, and consists of an axial and pericentral cells; further back, as shown in the fig., the lateral wings a, a, are the result of the continued growth and division of the pericentral cells, the anterio-posterior cells 6, b, remain rudimentary. After Agardh, ‘ Florideernes Morphologi,’ tab. 33, fig. 17. Fig. 21.—Ptilota plumosa Ag. Showing the development of a flattened thallus from the joining together of the “ veins” which represent the outline of a simpler filamentous form, by a membrane; a axis, 6 lateral branches with pinnate eae ent In this species the membrane only forms a broad wing to each vein. x 25. Fig. 22.—P. plumosa. Surface view of one of the lateral branches, showing the axial row of cells a, from which all the other cells originate. x 250. Fig. 23.—Transverse section of fig. 22, showing the development of the wing or membrane to be due to excessive growth and repeated division of the lateral pericentral cells. x 250. Fig. 24.—Delesseria (Wormskioldia) sanguinea Lamour. Apical part of one of the leaf-like portions of the thallus, showing the main axis a, with pinnately Notes on Hloridex. By George Massee. 563 characteristic of the Floridex are not developed, its true position is uncertain. For the same reason the genera Choreocolax and Pseudobiaste of Reinsch,* consisting of minute red filaments parasitic on or among the tissue of other algze, are passed over, since it does not follow that every red or pink seaweed belongs to the Floridex ; hence Chantransia, from a morphological point of view, stands at the base of the group. Harvey} divided alge into three primary groups, Chloro- spermex, Melanospermex, and Rhodospermex, distinguished by colour, the first beg green, the second olive-brown, and the third various shades of red or purple. This method of classification has been entirely superseded by one which is almost entirely carpo- logical ; the structure of the organs of reproduction and fruit being considered of primary importance in determining the position of a plant in the system. The adoption of this later method has ‘resulted in the entire rearrangement of the Chlorospermex and Melanospermex. The Rhodospermez still remain intact, but are now known as Floridex, an older name than Harvey’s, used by Agardh, and characterized by the presence of a more or less elongated filament called the trichogyne, which is the attenuated continuation of a cell known as the trichophore. When the motionless antherozoids are passively floated in contact with the trichogyne, they adhere to it, and fertilization takes place, followed by the formation of spores, either in the trichophore, or more arranged lateral branches, the whole resembling a feather-veined leaf. In this species the membrane is continuous, no space being left between the lateral branches, as in Ptilosa plumosa, fig. 21. Natural size. Fig. 25.—D. alata Lamour. Surface view of growing point. Neglecting for the moment the membranaceous portion of the frond, we find a well-developed apical cell a, but of the type characteristic of the lower filamentous forms. For some distance behind the apex, the axis is composed of a single row of superposed cells, each axial cell giving origin to a pair of opposite monosiphonous branches ; this arrangement recalls to mind such filamentous forms as Callithamnion pluma and C. plumula. Further back, the axial row is segmented into axial and peri- central cells 6, or the Polysiphonia type is reached. At first the axial cells are very short, but as they elongate, the lateral branches are not separated but remain organically connected, and by cell-division give origin to the membranous portion, at the same rate of increase as the elongation of the axial cell. The first septa that appear in connection with the development of the membrane, are parallel to the axis of growth of the branch, and cut the single superposed row of cells of which it before consisted, into a posterior and an anterior row. The posterior row, by repeated celJ-division, form the membrane, which when fully developed, consists of small polygonal cells; the anterior row of cells generally undergo no further division, but increase in length as the thallus becomes broader, so that they eventually appear as long narrow cells forming the lateral “ veins” which are in the older portions, like the axis, cut into axial and pericentral cells d. The apical cell of each lateral “ vein,” by segmentation, adds to its length c. x 300. * *Contributiones ad Algologiam et Fungologiam,’ 4to, Norimbergii, 1874-5. + ‘Nereis Boreali-Americana, ’ 4t0, New York, 1858. 2 P 2 564 Transactions of the Society. frequently in specialized adjacent cells, which with the trichophore and trichogyne collectively constitute, before fertilization the procarp, and after fertilization the cystocarp. The discovery of this very remarkable and complicated reproductive apparatus is due to the extensive researches of Dr. Bornet and M. Thuret,* whose magnificent illustrations and lucid descriptions leave little more to be expected in connection with the reproduction of the Floridex. In Agardh’s latest work on Algz,t Porphyra, Erythro- trichia, Goniotrichum, and Bangia, genera previously classed with the Floridex, are included in the Ulvacex, one leading character- istic of which is the possession of true zoospores. T’rom this it appears that he does not admit Berthold’s statement { that the species of Porphyra possess a trichogyne and trichophore, the latter eventually forming the cystocarp. The genus Chantransia as defined by Thuret, contained both marine and fresh-water types, frequently to be met with growing on other alge, under the form of minute tufts or velvety fringes, and characterized mostly by the monotypic structure of the vege- tative parts; but a more extended and critical examination has shown that only two of the supposed species possess antheridia, trichogynes, and cystocarps ; one fresh-water, C. cnvestiens Lenor., made the type of a new genus, Balbiania, by Sirodot; the other a marine species, C. corymbosa Bornet, which is therefore the only true Chantransia. It has been shown by Sirodot § that many of the fresh-water organisms formerly included under Chantransia, are nothing more than the prothalloid stages of various species of Batrachospermum, a genus of fresh-water alge belonging to the Floridex, and morphologically but little above Chantransia. It is interesting in connection with the development of the organs of reproduction characteristic of the Floridex, to note that in the genus Chantransia, where they first appear, out of numerous forms which, as already explained, from an examination of the vegetative parts alone, appear to be good members of the genus, only two have succeeded in producing sexual organs; the rest after remaining some time as asexual forms, give origin as it were to a sexual generation in Batrachospermum, whose reproductive organs closely resemble those met with in Chantransia and Balbiania, but in this second generation the vegetative part has become rather more complex. A repetition of what has been described is met with in Calli- thamnion, a typical Floridean genus in its most perfect develop- * “Recherches sur la fécondation des Floridées,” Ann. Sci. Nat., vii. (1867). “Notes Algologiques,’ fase. i, ii., Paris, 1876-8. + “Til Algernes Systematik,” Lunds Arsskrift, xix. (1882-83) 177 pp. and 4 pls. } Mittheil. aus der Zoolog. Station zu Neapel, iii. (1882) pp. 393-536, 3 pls. § “ Observations sur le développement des algues d’eau douce composant le genre Batrachospermum,” Bull. Soc. Bot. France, xxii. (1875). Notes on Floridex. By George Massee. 565 ment; but towards the base of the genus we have C. rothiz, in which antheridia and cystocarps are unknown, but characteristic tetragonidia (= tetraspores) are present; yet lower down we meet with plants agreeing exactly in thallus structure with C. roth, but without cystocarps, and instead of producing tetragonidia, we find undivided gonidia produced in cells terminating lateral branches, and occupying exactly the same position as the tetragonidia in C. rothii. The species with undivided gonidia and no sexual organs, including the old Callithamnion virgatulum of Harvey, and others, now constitute the genus Trentepohlia. The asexual or Chantransia stage of Batrachospermum can reproduce itself for several generations by sporules, and continues to do so when growing in dark or shaded situations, while the sexual or Batra- chospermum stage is mostly produced when growing in the light. On this account it is difficult to demonstrate the genetic connection _ between the two stages, which, however, has been done by Sirodot * in several species, and he considers it as a true example of alterna- tion of generations. ‘This of course depends on the author’s defini- tion of that term ; it is certainly not in any sense an example of alternation of generations as defined by Sachs,t where during the entire course of development, the plant starts twice from a single cell; the first or sexual stage from the germination of a spore, the second asexual stage from the oospore. In Batrachospermum, the sexual stage is developed last, and not from a single cell pro- duced by the Chantransia, but as a direct vegetative continuation of the latter. It illustrates what Sachs terms “alternation of axes.’ { The oospore produced by the Batrachospermum stage, never reproduces itself directly, but on germination, gives origin to a minute cushion of polyhedral cells, which Sirodot terms the prothallus, and without developing further, can reproduce itself by sporules. Sooner or later it generally gives origin to branched filaments which develope into the Chantransta condition, this in turn can produce itself by sporules; if vegetative development proceeds further, the sexual or Batrachospermum stage results. A well-developed apical cell is always present in Ploridex, which in the simpler forms is large, cylindrical, and with a rounded anterior end. ‘This mother-cell is divided into two daughter-cells by a straight or slightly curved septum, transverse to the axis of growth, the apical portion growing until it equals its mother-cell im size, when division again takes place in the same manner. When the thallus consists of a single row of superposed cells, the segment, or posterior daughter-cell is at first dise-shaped, the two * “Ties Batrachospermes, organisation, fonctions, développement, classifica- tion,” Bull. Soc. Bot. France, xxxi. (1884). + ‘Text-Book of Botany,’ second English ed., 1882, p. 228. t Tom. cit., p. 228. 566 Transactions of the Society. principal walls being flat and parallel to each other, and the outer wall cylindrical. In the more highly developed forms, the apical cell is smaller than in the simpler species, the usual shape, as seen from above, being that of a transverse section of a bi-convex lens; sometimes the two faces are equally curved, as in Rhodymenia laciniata ; generally the anterior wall is more convex than the posterior. ‘The segment is watchglass-shaped with the concave wall next the base of the apical cell ; this segment by subdivision gives origin to the mass of cells forming the thallus. The mode of segmentation characteristic of vascular cryptogams, in which several daughter- cells of equal value are simultaneously cut off from the apical cell, does not occur in this group, although when growth is very active the segment is so soon cut up, that its components present the appearance of having been directly cut off from the apical cell; but later in the season, when cell-development is somewhat retarded, the segment can be seen intact. In all cases when the thallus is composed of more than single rows of cells, the segment first divides into an axial cell, surrounded by a varying number of pericentral cells; these last, owing to the watchglass shape of the seement, stand at a higher level than the apical cell, which thus becomes buried in the surrounding tissue, consequently the organic apex or growing point is much below the geometric apex of the thallus. The species of Chondriopsis and Lawrencia illustrate this mode of growth, which also occurs in some monosiphonous genera as Batrachospermum and Halurus, where the last whorl of branches, which are lateral extensions of the segment, arch over the apical cell. Callithamnion roseum and C. polyspermum present the peculiarity of having two distinct methods of segmentation of the apical cell, which in the main axis is cut into two daughter-cells by a septum inclined at an angle of 45° to the axis of growth; the septa are all in the same plane, but slope alternately to right and left, so that the cells just below the growing point are more or less triangular in shape, and the septa form a zigzag line; as the cells increase in size, the triangular form is lost, and at some distance behind the apex they are cylindrical and the septa transverse. In - all the branches the segments are cut off by septa, which are from the first at right angles to the axis of growth. Branches originate either by lateral budding or by division of the apical cell. The first method is most general, the branches showing as minute protuberances from the segment, as in Péilota elegans and Cystocloniwm purpurascens, or more frequently from a cell further back, as in Ahnfeldtia plicata and Plocamiwm cocet- neum. All species with a flattened thallus appear to branch by this method. According to Sachs* the lateral branches show as promi- * ¢Text-Book of Botany,’ second English ed., 1882, p. 140, fig. 108. Notes on Floridex. By George Massee. 567 nences on the apical cell in Stypocaulon seoparium. Division of the apical cell occurs in some highly differentiated genera as Cera- mium, Pandorea, and Dasya. Branches always originate directly from axial cells, and even when the axis is polysiphonous and densely corticated, their organic connection with axial cells can be demonstrated. Sometimes, as in Dasya coccinea, adventitious branches are present which originate from cortical cells. These present the appearance of hairs and consist of a single row of cells. When an apical cell is about to divide to form two branches, imme- diately after a daughter-cell has been cut off, and while the apical cell is still small, it is divided into two equal portions by the appear- ance of a septum in the direction of the axis of growth of the branch. If the branches are all developed in one plane, this septum is at right angles to the plane of the branches ; but when they are arranged in a spiral, the septum is at right angles to the plane of the branch immediately below. After the formation of the vertical “ septum in the apical cell, the two daughter-cells commence growth, but there is no connection between the origin of branches and their ultimate arrangement. If the two cells develope at the same rate, and diverge at equal angles from the direction of the podium from which they originate, a dichotomy is the result, as may be seen in Pandorea traversiz, and sometimes in Dasya coccinea. If one cell grows more vigorously than the other, and in the same direction as the podium, the other growing at an angle, and resembling a lateral branch, a sympodial arrangement results, as is usual in Dasya coccinea. When branches originate as lateral protuberances the ultimate arrangement may be dichotomous, as in Callithamnion corymbosum ; sympodial, in C. tetragonum; or monopodial in C. polyspermum, depending on the relative development and direc- tion taken by the branch and the axis from which it springs. In the filamentous members of the Floridew, in which the axial cells remain, “protoplasmic continuity,” which is so conspicuously developed in the group, enables an observer to determine with certainty the mode of origin of any branch, even when fully developed, depending on the number and arrangement of the threads of protoplasm connecting the protoplasts of adjoining cells. When the branch originates as a lateral protuberance, the curved septum that cuts it off from the parent cell is pierced by one protoplasmic thread, which connects the protoplasm of the one-celled branch with that of its mother-cell. This one-celled branch is an apical cell, from which in due course is cut off a segment. This seg- ment constitutes the basal cell of the new branch, and is never connected by protoplasmic threads with more than ¢wo cells, the one from which it was segmented below, and the one cut off from it above. When branches originate from the division of an apical cell, the two sister cells resulting from the formation of a vertical 568 Transactions of the Society. septum in the apical cell, are connected laterally by a protoplasmic thread passing through the vertical septum. Lach is the apical cell of a new branch, which eventually, owing to the appearance of a transverse septum, is cut up into a segment and an apical cell. Each segment forms the basal cell of a new branch, and is joined to three other cells by protoplasmic threads; to its sister basal cell, laterally ; to the cell below, from which it was seg- mented, and to the cell above, which is the second cell of the new branch. The wall in young cells consists at first of pure cellulose, and remains as such until, owing to surface growth, the cell has in- creased considerably in size. Surface growth is rarely uniform over all points of a cell-wall, and as a rule is much more vigorous in the direction of the axis of growth than transverse, so that a cell originally presenting the appearance of a disc much broader than long, becomes not unfrequently ten, or even twenty times as long as broad. When pericentral cells are cut off from an axial cell by vertical septa, they grow most in the same direction as the latter, and usually at the same rate, thus giving origin to a stem eom- posed of fascicles of superposed cells of equal length, as in the genus Polysiphonia ; but when branches spring from an axis their com- ponent cells increase most in the direction taken by the new grow- ing point, which may be at right angles to that of the parent stem. Cortical cells, or those developed for the purpose of adding to the substance of the axis, differ in origin from branches which form new axes. ‘The latter appear as protuberances before separation from the mother-ceil by a septum, while the first indication of cortical cells is the presence of curved septa, cutting off portions of the mother-cell, soon after its segmentation from the apical cell. This mode of cortical cell development can be well studied in the genus Polysiphonia. In some instances the cortication of the stem is due to adpressed branches, as in the genus Ceramzum, where the stem consists of a single row of superposed cells. From the anterior end of each cell, as in Batrachospermum, a whorl of branches originate, which instead of developing in a normal manner, and leaving the stem at an angle, remain adpressed to it, and by cell development cover it more or less completely. In Batrachospermum the whorled branches spread more or less at right angles to the stem, but the secondary branch which springs from the basal cell of each of the whorls of branches, grows downwards and is closely adpressed to the stem. These corticating branches continue to grow downwards until they reach the base of the stem or nearly so, where they act as rhizoids, and assist in fixing the plant, so that towards the base the stem of an old plant is densely corticated, whereas near the growing point the adpressed branches may be seen starting from Notes on Floridex. By George Massee. 569 the basal cells of the branches, and not having yet reached the next whorl of branches below, between which they pass in their down- ward growth. In some species these corticating branches them- selves branch, the ultimate branches developing at right angles to the stem, and presenting the appearance of hairs. In the genus Crouania, this mode of cortication is yet more complex. A third, and by far the most universal method of cortication results from branches which spring from axial cells in a scattered or whorled manner, becoming densely corymbose and of equal length, the cells decreasing in size from the base tothe tips of the branches. The cells of adjoining branches are agglutinated together, so that a dense continuous pseudo-parenchymatous cortex of small closely- packed cells results, the interior of the thallus consisting of com- paratively few large cells. This type of cortication is well shown in the genera Caulocanthus, Halymenia, and Glotosiphonia. The growth in diameter of cells is generally uniform when free from pressure and not giving origin to lateral branches, and the transverse section circular, while the zone of growth that adds to the length of the cell may be most vigorous near the posterior end, as in the genus Ceraméwm, where the axial cells when young are thin discs, from the anterior margin of which are cut off the cortical cells, the naked portion below increasing much in length, while no increase in the length of the cell takes place anterior to the origin of the cortical cells. In the genus Polysiphonia growth is uniform or nearly so throughout the entire length of the cell, which is also disc-shaped at first, and soon segmented into an axial surrounded by cortical or pericentral cells, the protoplasts being connected by well-defined threads of protoplasm. After having attained their full size the connecting threads are seen to occupy the central portion of the length of the cells, showing an equal rate of growth in length anterior and posterior to what was origi- nally the middle of the length of the cell. The first differentiation observable in the cellulose of external cells is the formation of a cuticle, which in the fully developed plant can be shown to exist as a continuous pellicle investing every part. It resists for a long time the action of acids and alkalies, and when treated with chlor- iodide of zine or sulphuric acid and iodine, assumes a brown or yellowish colour. Surface growth, or increase in size of the cell- wall, appears to be due to intussusception, as micro-chemical tests show a uniformity of composition throughout ; but the thickening of the cell-wall, so conspicuous in many seaweeds, is clearly due to apposition, the cell-wall when young changing to a bright blue when treated with sulphuric acid and iodine, but as the wall increases in thickness the innermost and last added portion alone shows this reaction, the outer portion becoming brown or reddish, eradually passing into blue as it approaches the inside. Worms- 570 Transactions of the Society. kioldia sanguinea is favourable for this experiment. The cell-wall in young leaf-like portions of the thallus being thin, while the older axial parts have the walls much thickened and exhibiting very clearly lines of stratification and striation. An additional proof in favour of the thickening being due to apposition, is met with in -Ceramium rubrum, Polysiphonia fastigiata, and other species of the same genus, where the axial cell, after a certain amount of surface growth, is cylindrical with flat ends, the diameter of the posterior end being often slightly greater than that of the body of the cell, owing to a slight contraction of the cylindrical outer wall. This contraction leaves a little channel inside the base of the cell, and portions of the protoplasm which occupy this channel are cut off from the rest by the thickening matter subsequently deposited, which does not in all places follow the indenture of the wall. These isolated portions of protoplasm, by subsequent growth, burst through between the pericentral cells and form irregular cortical cells on the surface of the stem. In most seaweeds portions of the thickened cell-walls, more especially in the younger parts, become resolved into mucilage, which in species with a fleshy thallus, cements cells together that were otherwise free from each other, so that a transverse section presents the appearance of com- pact cellular tissue. It is due to the presence of this mucilage that most algze adhere so firmly to paper when dried. In the simpler green seaweeds belonging to Harvey’s Chloro- spermee, illustrated by such genera as Plewrococcus and Glwocapsa, we have probably the prototypes of existing vegetation. In such the mode of reproduction is vegetative, and effected by fission, the entire mass of the individual, after reaching a given stage, break- ing up into a definite number of pieces, frequently four, each capable of assimilating food until it reaches the size of its parent, when fission is repeated. This mode of reproduction is also characteristic of the lowest forms of animal life. It is interesting to note, that in those organisms where reproduction is effected by fission, there is no provision for death, as generally understood. A Plewrococcus after haying performed all the chemical and physical functions necessary for the perfect developement of the species, loses its individuality when fission takes place, but all the material appropriated by life is retained, each succeeding generation reducing the limited supply of available food capable of being converted into its own substance. The false start made by the newly-evolved force life, which would—if this primary idea of vitalizing and re- taining in that condition all available material had been adhered to —have resulted in its own extermination on the exhaustion of the already existing supply of food, was corrected, and the continuance of life for an indefinite period secured, so far as depends on the presence of an inexhaustible supply of food, by the evolution of a Notes on Floridex. By George Massee. 571 second type of reproduction which manifested itself in some of the species of the same primitive family of plants, by which, after a limited period of existence as an individual, the sum total of forces constituting its life became concentrated in a small portion possess- ing the power of reproducing its like, the greater bulk of the individual dying, becoming reduced to its elements, and soon ready to be used again as food by succeeding generations. This second form of reproduction rendered possible cross-fertili- zation, which has proved to be a prime factor in enabling life to evolve from primitive types, throngh its various phases up to existing forms. Sexual differentiation, and the various contrivances for preventing self-fertilization, and at the same time favouring cross- fertilization, which have been brought so prominently before the public in connection with flowering plants, and popularly believed to be peculiar to the higher forms of life, are to be met with in the various groups of alge; the structural differences in this ‘matter between algze and phanerogams being the result of the markedly different conditions under which they respectively exist. Algee, in common with all cryptogams, depend on water as the motor agent by which the union of the two bodies connected with sexual reproduction is effected; consequently the various struc- tures that enable flowering plants to utilize the wind or insects as agents in transporting the pollen to the stigma are absent from the former. In alge, again, we trace the evolution from primitive isolated unicellular forms, as Hremosphxra, to the more complicated multi- cellular types, illustrated. by the brown and red seaweeds, showing marked differentiation and division of labour, through the numerous stages of cell-colonies composed of unicellular organisms each retaining its original morphological and physiological characteristics, but mechanically held together by mucus. In the Floridex, if we except a few minute parasitic forms included by Reinsch* on account of their red colour, all the members are multicellular, but, as described above, consist in the simplest types of threads composed of a single row of cells placed end to end. In addition to the sexual reproductive organs, a very characteristic and more universal vegetative method occurs, consisting of the contents of certain cells breaking up when mature into four portions, hence known as tetraspores or tetragonidia. It is remarkable that the exact method of reproduction characteristic of the lowest forms of plant life should reappear in this highly developed family and its near relation Dictyotex, after having been superseded in the higher green and in all the brown seaweeds. ‘Tetrasporic individuals are, with very rare exceptions, distinct from those bearing sexual organs. * Reinsch, tom. cit. 572 Transactions of the Society. Farlow and Bornet mention a few species in which individuals have been met having both kinds on the same individual, and we once found a single plant of Polysiphonia byssoides bearing well- developed tetraspores and cystocarps. Some algologists in de- scribing the species included under Palmellacea: and other primitive families, use the term “ multiplication” to denote what we have termed vegetative reproduction, and “ propagation ” when reproduc- tion is effected by specialized portions, sexual or otherwise, hence we presume the terms would be equally applicable to define the two methods of reproduction met with in the Florideze. In acarpological arrangement Floridez stand at the head of the algal family although the vegetative parts, as a rule, are less developed than in the brown seaweeds belonging to Fucacee and Laminarier. The following are the most marked types of thallus develop- ment met with in Floridex. 1. When the substance and outline depend entirely on the development of branches of definite growth, springing ina whorled or scattered manner from axial cells; these branches are of equal length and densely corymbose at the tips, which are cemented together, forming a false parenchymatous tissue towards the surface of the thallus, the interior remaining spongy. If the branches all develope equally a cylindrical thallus results, but if growth is unequal and most pronounced in one plane, a flat thallus is produced. The flattened thallus is always evolved from a cylindrical type, in other words the mode of branch arrangement observable in a flat thallus can always be met with in a less differentiated manner in the cylindrical stage, and connecting the two there is every transition. The following genera illustrate the sequence of development of this type :— Batrachospermum, branches in whorls, equally developed, whorls distant. Crouania (schousbeet 'Thur.), branches in approximate whorls, but not agglutinated together. Calosiphonia (finisterre Crouan), whorls equally developed and approximate, the external cells agglutinated together and form- ing a continuous cylindrical thallus. In the above example the branches spring from a single row of axial cells ; in Solieria (chordalis J. Ag.) the thallus is cylindrical as in Calosiphonia, but instead of a single axial row of cells there are several rows, from which the branches spring. Polyceelia shows the transition from a cylindrical to a flattened thallus. The branches originate from a single axial row of cells; but the lateral branches grow much longer than the anterio-pos- terior ones, producing a thallus with a more or less compressed Notes on Floridex. By George Massee. 573 or elliptical outline in section, whereas in Halymenia and numerous other genera, the thallus is broad and membranaceous, owing to excessive development of the lateral branches. 2. In the second type the substance of the thallus does not depend on the presence of branches, but on a definite number of pericentral cells or siphons, which are cut off from the axial cells by curved tangential septa. ‘These grow at the same rate as the axial cells, so that the thallus consists of fascicles of superposed cells of equal length. In some species a second set of irregular corticating ceils are present outside, and alternate with the siphons, consisting of adpressed branches, originating at the nodes ; sometimes in Poly- siphonia, trom portions of protoplasm imprisoned by the apposition of cellulose, during the thickening of the cell-wall, as described above. The following genera illustrate this mode of thallus forma- tion: Polystphonia, Bostrychia, Dasya. When flattened, as in Odonthalia, the fascicled arrangement is masked, owing to subse- “quent growth, but the typical polysiphonous structure is clearly seen in the younger portions. 3. In a third type the thallus is typically flat and membra- naceous, resulting from the branches of a filamentous thallus, as in Callithamnion, being connected by a web or membrane of tissue. In some species the connecting membrane is only one cell thick, in others it is composed of several layers of cells, owing to subsequent cell-division parallel to the surface. In most species the evidence of their filamentous origin can still be traced in the go- called “veins” in the membranaceous thallus, and microscopic examination clearly shows that these veins give origin to the cells which, by division, form the flattened portion. The arrangement of the veins may be dichotomous and develope into a flabellate or irregularly expanded thallus, as in Nitophyllum and Callophyllis ; or pinnate, as in Delesseria, where the British species furnish a most interesting sequence from the filamentous D. angustissima to D. (Wormskioldia) sanguinea, where each portion of the thallus, under favourable conditions, resembles an obovate or oblong leaf, from four to seven inches long, with a strong midrib, giving off secondary and tertiary veins corresponding to the cell traces. A further proof of the statement as to the evolution of the membrana- ceous genera mentioned, as well as others, from filamentous ancestors, is the fact well known to algologists, that the form and expansion of the thallus in this type is one of the most untrust- worthy of characters ; a well-selected series of most species illus- trating a transition from filamentous to broadly expanded forms ; and further, it is by no means unusual to meet with the various transitions on the same thallus, as shown in Harvey’s figure of Halymenia ligulata Ag. 574 SUMMARY OF CURRENT RESEARCHES RELATING TO SUMMARY OF CURRENT RESEARCHES RELATING TO TiO Oar OG Yo ANDY BOT ANE (principally Invertebrata and Cryptogamia), MICROSCOPY, &c., INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* ZOOLOGY. A. VERTEBRATA :—Embryology, Histology, and General. a. Embryology.t Spermatogenesis in Mammals.{—Herr C. Benda, continuing his account § of mammalian spermatogenesis (which is in essential agree- ment with that lately given by Mr. H. H. Brown),|| discusses the existence of an internal process from the ‘supporting cell.” The presence of a single process he regards as the artificial result of re- agents, but affirms the existence of a brush-like bundle of fine filaments with which the young sperms become connected. He describes the elongation and subsequent retraction of the supporting cell, and shows how in consequence of the latter, which is unusually marked in the rat, the sperms come to be displaced even to the extent of reaching the wall of the canal. The pointed pole of the young sperm represents the position first connected with the supporting cell, and towards this pole the nucleus moves, exhibiting a chromatin body which points in the same direc- tion. The behaviour of this apical knob in uniting with the process of the supporting cell, and the further modifications of the sperm-cells are briefly described. Blastodermic Vesicle in Mammals.§—After giving a brief résumé of Van Beneden’s account of the segmentation of the rabbit’s ovam, and referring to the theories of various writers as to the meaning and * The Society are not intended to be denoted by the editorial “ we,” and they do not hold themselves responsible for the views of the authors of the papers noted, nor for any claim to novelty or otherwise made by them. The object of this part of the Journal is to present a summary of the papers as actually published, and to describe and illustrate Instruments, Apparatus, &., which are either new or have not been previously described in this country. + This section includes not only papers relating to Embryology properly so called, but also those dealing with processes of Evolution, Development, and Reproduction, and with allied subjects. + Arch. f. Anat. u. Physiol. (Physiol. Abth.), 1886, pp. 386-8. § Cf. this Journal, ante, p. 209. - || Cf. this Journal, v. (1885) p. 783. 4 Scientif. Proc. R. Dublin Soc., iv. (1885) pp. 536-45 (7 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 57a use of the “ outer layer” of the segmented ovum, Prof. A. C. Haddon suggests an explanation of these facts. The ‘outer layer” corresponds to the non-embryonic epiblast of the area opaca: the middle layer of the blastoderm is the embryonic epiblast, and the deep, flat cells, form the hypoblast. The “ blasto- pore” of Van Beneden indicates in an exaggerated manner the separation between the embryonic and non-embryonic germinal layers, since the blastoderm has sunk into the blastodermic vesicle owing to the absence of yolk. The author gives a series of woodcuts of hypothetical mammalian eggs, in which is shown the manner in which the true embryonic epiblast (which lies at first, as in fowl’s egg, on the surface of the yolk) sinks into the yolkless vesicle; the non-embryonic epiblast, which has now extended round the blastodermic vesicle, owing to the loss of yolk, gradually grows over the in-sunk embryonic epiblast : the stage before the meeting of the sides of the embryonic epiblast being represented by the stage in the actual mammalian egg when Van Beneden’s “ blastopore” is present. The cells of the embryonic ‘epiblast now arrange themselves in a definite layer below the non- embryonic epiblast or covering cells, and below it again is the hypoblast, as in the actual mammalian blastodermic vesicle. The segmentation of the mammal’s ovum is very abbreviated; the first cleavage furrow demarcates the embryo from the yolk-sac. The author then refers to the researches of Agassiz and Whitman and others as to the orientation of the primitive segmentation spheres. In the marsupials it has been shown that the subzonal membrane of the yolk-sac serves to attach the embryo to the wall of the uterus, either by vascular villi or by simple amceboid processes of the cells: so in the rabbit the covering cells, or non-embryonic epiblast of the blastodermic vesicle (i.e. yolk-sac) “‘form the first adhesion between the ovum and the parent.” This temporary adhesion in the Eutheria is later on replaced by allantoic villi. Horny Investments of the Eggs of Scyllium stellare.*—Herr C. F. W. Krukenberg gives a full account of his experiments on the egg-shells of Scyllium stellare, and points out that in some the substance resembles cow’s-horn and human hair. 8. Histology.t+ Phenomena of the Division of the Cell-nucleus.{—M. L. Guignard directs attention to some of the phenomena which accompany the division of the nucleus of the cell, with especial reference to the recent theories of M. Degagny. That botanist teaches that the nuclei disappear progressively as the equatorial zone becomes colourable. This is denied by M. Guignard, who points out that the coloration of the equatorial zone is due not to nuclei but rather to the cyto- * MT. Zool. Stat. Neapel, vi. (1885) pp. 286-96. + This section is limited to papers relating to Cells and Fibres. ¢ Comptes Rendus, cii. (1886) pp. 1036-8. 576 SUMMARY OF CURRENT RESEARCHES RELATING TO plasmic granulations which play an important part in the formation of the cellular plate, and of which M. Degagny makes no mention. The figured element must not be confounded with the amorphous nuclear fluid; methylene-blue is not a suitable substance for dif- ferentiating the elements which enter into the constitution of the nucleus or of the cell. New Element in the Blood.*—After giving his own observations on the “new element” of the blood, for which he adopts the name plaque, Mr. G. T. Kemp gives an historical review of the literature, on the subject, and the theories as to the origin and function of these plaques. He describes their histology and micro-chemistry, and concludes with a bibliography of the subject. The results of his own and other observations he summarizes in the following words :— 1. In addition to the red corpuscles and leucocytes, the blood normally contains a third histological element, the plaques. 2. Although strong resemblances exist between the plaques and the other histological elements of the blood, there is not yet sufficient evidence to establish a genetic connection. We are therefore obliged, for the present at least, to regard the plaques as independent elements. 3. When the blood is drawn the plaques break down almost immediately. ‘This is not true of any other element in the blood. 4, The breaking down of the plaques is intimately connected, in its time-relations at least, with the clotting of the blood. 5. The connection between the breaking down of the plaques and the coagulation of the blood is not histological, but chemical, i. e. the plaques appear to give a soluble substance which is active in coagulation. 6. The active agent in question is most probably fibrin-ferment. 7. Fibrin is deposited histologically independent of any of the cellular elements of the blood. 8. When the clot is very scant, fibrin is deposited as long, needle- shaped, crystal-like bodies. Histology of Central Nervous System.j—Prof. H. Gierke com- municates the first portion of a research on the histology of the central nervous system, which consists of a detailed account of the supporting substance (“Stiitzsubstanz”) in which the nervous elements are embraced. His results are based on a study of numerous types from fishes upwards to man. I. Technical Methods.—(a) For the indispensable isolation process Dr. Gierke recommends extremely dilute chromic acid and salts, Ranvier’s “ alcohol & tiers,” but especially a solution discovered by Landois, consisting of (1) neutral chromate of ammonia, 5 gr.; (2) phosphate of potassium, 5 gr.; (3) sulphate of soda, 5 gr.; (4) dis- tilled water, 100 gr. (b) For staining, he found carmine by far the most effective colouring substance, in the common associations with * Stud. Biol. Laborat. Johns-Hopkins Univ., iii. (1886) pp. 294-339 (1 pl.). + Arch, f. Mikr. Anat., xxv. (1885) pp. 441-554 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. ay hy ammonia, or with alum, or with a sodic base. He also recommends strongly Heidenhain’s hematoxylin. (c) Hardening was best effected by a solution of 15-23 per cent. double chromate of ammonia. (d Imbedding cannot be in any way satisfactorily accomplished by paraffin, wax, or gum, but the celloidin method recommended by Schiefferdecker was found most effective. (e) Dr. Gierke insists especially on the necessity of having fresh material and thin sections, and attributes many discrepancies of result to the absence of these essential conditions. After noting briefly some of the current descriptions of the histology of the central nervous system, and emphasizing especially the incorrectness of the phrase connective tissue, so often applied to the supporting substance, he selects as most convenient Virchow’s term, “ neuroglia,” including in that both the amorphous ground-substance and the definite cellular elements, which together form the matrix in which the nervous elements are im- bedded. These two parts make up the whole neuroglia; he denies the existence of elastic fibres, connective-tissue fibrils, free nuclei, &e. The only structures which occur are lymphoid cells which have wandered in, or embryonic cells which have persisted unmodified. The matriz—The ground-substance or amorphous matrix forms along with the imbedded cellular elements (1) the outer and inner enveloping mass of the central nervous system, (2) the matrix of the grey substance, and (8) the stronger strands penetrating the white substance. In the grey matter the ground-substance is abundant, varying in different mammals in quantitative development apparently in inverse proportion to the development of the nervous elements, i.e. becoming less as the intelligence increases. It is uniform throughout, homogeneous, structureless, transparent—a soft but firm, not fiuid, elastic albuminoid substance. The alleged existence of imbedded molecules, on which so much stress has been laid by some, e.g. Rindfleisch, rests on a misinterpretation of cross sections of fibres, fibrils, and glia-cell processes; the granular character of the ground-substance described by even such accurate observers as Henle, has a similar explanation—the granules belong to the glia-cells. Cellular elements of the neuroglia.—The neuroglia-cells, often called spider-cells, form the greater part of the neuroglia, extending through every portion of the matrix and forming with their long uniting processes a supporting meshwork. They vary extremely in size, form, nature of processes, and even in consistence, but exhibit relatively constant characters in definite localities. Processes.—There are no glia-cells without processes, and though cells with only one do rarely occur, there are usually many from each cell. In the white substance the individual processes some- times interlace before breaking up into extremely fine branches. The marvellous network of processes is even narrower and finer in the grey substance. Form and size of the cells—The cells have of course no outer envelope of any kind. The differences in size are extreme, varying with the size of the nucleus, the development of processes, and the degree of horny modification. Two prominent types, connected Ser. 2.—Vot. VI. 2 Q 578 SUMMARY OF CURRENT RESEARCHES RELATING TO indissolubly by intermediate forms, are distinguishable :—(1) cells in which the nucleus is relatively very large and often indeed apparently naked, at least always forming the chief part of the cell; from the nucleus itself or from the little protoplasm round it, a few processes arise, which are always extremely delicate and branching; these cells are most abundant in the grey matter. (2) cells in which the nucleus is either absent, stunted, or ill- defined, but with well-developed, and in adults well-cornified cell- bodies, with firm and numerous processes. The differences between these two forms are described in great detail. Cornification.—Neurokeratin was described by Ewald and Kihne in 1877; Gierke has shown the exact mode of its origin from the gradual cornification of the cells and their processes. In its study use was made of the digestive method (with pepsin and trypsin), whose application is due to the above-named investigators. While the keratin-forming process advances the nucleus degenerates, gets smaller and crumpled, and finally disappears in the cell. The further this degeneration of the nucleus has advanced, the greater the resistance of the cell to acids and alkalies. In the second form of cell, where the nucleus predominates, the keratin-modification is confined to the processes ; neither the nucleus nor the small cell-body are cornified. Development.—In the embryonic nerve-strand the cells are of course alike, nor after the nerve-fibres are differentiated are there any observable differences in the roundish polygonal “ Stiitzzellen,” and even when the glia-cells have developed their characteristic pro- cesses they are for a while quite homogeneous. Glia-cells and nerve- cells have emphatically an identical ectodermic origin; the former certainly do not come in from outside with the blood-vessels or in any other way. Gierke protests emphatically, as we have noted, against the common use of the phrase “connective tissue of the central nervous system.” The neuroglia is entirely ectodermic, connective tissue is mesodermic, and the histological structure of the two is very different. He describes in greater detail the history of the “epithelial glia- cells” which limit the glia round the central cavities of the brain and spinal cord, noting especially the latter. At first several layers of long elliptical or spindle-shaped cells are seen regularly arranged round the central canal. The peripheral ends of these cells are narrowed and prolonged in a process in the direction of the longi- tudinal axis of the cell, and can be followed through the grey and white matter to the margin of the cord. The outer cells of these layers become much modified from without inwards; from them originate both ganglion-cells and multipolar neuroglia-cells ; a single layer is at length left—the epithelium of the central canal. Processes from the lateral “ epithelial cells” join the fibres of the glia mesh- work of the substantiva gelatinosa centralis, or penetrating through this unite with the fibres in the grey substance. The epithelial cells before and behind the canal send sagittal processes anteriorly and posteriorly between the symmetrical halves of the cord, uniting with the connective-tissue sheath. Independent fibrils may arise by losing ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 their connection with cells from which they arose as processes. Such processes from the epithelial cells come to form somewhat irregular bundles between the anterior and posterior horns and in the longi- tudinal fissures. They run often into the pia and unite with it, while from the pia connective-tissue fibrils, usually in association with blood-vessels, run parallel to the former out to the commissural region of the cord. Thus the so-called “pia processes” filling up longitudinal fissures have partly this connective-tissue origin, but are also in part, and usually for the most part, cornified glia-fibres, either direct processes of the nearest “ epithelial cells” of the central canal, or fibres which have become independent. As to the amorphous element, the structureless ground-substance or matrix, Dr. Gierke is inclined to refer its origin to the gradual change of the embryonic cells, though he does not exclude the possibility of its being in part excreted by the glia-cells. In the great subsequent growth of grey matter round about the epithelium and substantiva gelatinosa centralis, glia-cells are seen, originating either from those of the inner layer, or more probably from a new modification of embryonic cells. The details as to the modifications of the glia-cells, the development of processes, &c., cannot be summarized. In the brain the elements of the neuroglia are essentially similar to those of the spinal cord; the two types of cells are not, however, so well marked ; the cell-bodies, especially in the molecular layers of the cerebellum, sometimes almost disappear, so that their former position is only indicated by a small knot from which the processes diverge; while the glia-cells in the grey sheath of the cerebrum exhibit as a result of cornification a peculiar nuclear modification, as the nuclei, instead of shrivelling smaller and smaller, retain their size but lose their sharp contour; these cells are further peculiar in their very granular appearance. Function —The function of the glia is to surround and protect the nervous elements; it penetrates every portion of the central nervous system; the whole network of glia-cells is continuous, the ground- substance and the nervous elements fill up the meshes. Specially differentiated is the glia-sheath which surrounds the whole central organ and separates the inner substance from the pia mater. It is always to be found where the pia covers the surface ; it effects on the one hand the peculiar union between the surface of the nervous organ and the pia, and forms the constant narrow lymph spaces between them, while it is also obviously protective and serves as a sort of basis for the neuroglia network. Its variations and exact histological relations are intimately described, especially as they occur in the pike. The cavities of the central nervous organ are surrounded by layers of neuroglia in which few nervous elements occur; the “ granular tissue” often described is produced by cross sections of processes. Round the cavity of the ventricle this tissue is limited by a layer of epithelial-like cells, sometimes finely ciliated, sometimes flattened. They are in close union with the neuroglia and are modified glia-cells, Besides the outer glia-sheath and the inner lining of the central cavities, the glia framework, with its associated network, is described 2 2 580 SUMMARY OF OURRENT RESEARCHES RELATING TO in its variations in grey and white substance, and in different regions of these. The firmness of the glia-cells seems to vary inversely with that of the nerve-cells. Inter alia Prof. Gierke notes that the nerve- fibres are everywhere enveloped in an ensheathing neuroglia network, whose knots represent glia-cells, and the threads processes. The main threads are bound together by glia-fibres, and the resulting net- work nerve-fibre sheath is of extreme fineness. He maintains that the medulla-containing nerve-fibres are never imbedded directly in the matrix, but are always separated from it by the formed elements of the neuroglia. The glia framework of the white substance is formed as usual from cells and matrix, but nerve-fibres sometimes occupy the meshes of the network. 'The arrangement and varying quantitative development of the elements, their relation to the blood- vessels which accompany the stronger strands, &c., are next discussed. The quantitative development of the neuroglia in the white substance of the spinal cord is proportionately less in the lower vertebrates than in mammals, but Dr. Gierke is unable yet to formulate any certain law. The memoir ends with a comparison of the development of neuroglia in different regions of the white substance. To this most elaborate research, dealing specially as yet only with the sup- porting substance, a continuation is promised, which, if as thorough as the above, will go far to justify the author’s assurance that the central nervous system “which has been hitherto so divergently described and in its essential nature really so little known, will henceforth be one of the best known tissues of the body.” y. General.* Parietal Eye of Hatteria.t—Mr. W. Baldwin Spencer reports a remarkable discovery—the presence of a median parietal, or as it might more justly be called interparietal, eye in Hatteria punctata, the curious lizard of New Zealand. The epiphysis cerebri of amphibians and reptiles becomes divided into two parts, the proximal of which remains connected with the brain, while the distal is a bladder-shaped structure. In Anguis fragilis this distal part, as Von Graaf finds, loses all connection with the brain, and developes into a structure resembling a highly organized invertebrate eye; no nerve, however, is connected with it. In Hatteria the similar eye-like organ is provided with a well-marked nerve. The eye is enclosed in a capsule of connective tissue; anteriorly there is a lens which forms the anterior boundary of a vesicle, the walls of which are formed from within outwards of the following layers :—(1) a not well-marked layer, (2) a layer of rods imbedded in dark-brown pigment, (3) a double or triple row of nuclei, (4) a clear layer which may be called the molecular, and (5) a layer of nuclei two or three rows deep. The nerve which enters the eye posteriorly spreads its fibres round the vesicle. A blood-vessel ramifies in the surrounding connective tissue. The eye lies exactly in the median line, and the nerve is single; the latter appears to represent the stalk connecting the distal with the proximal outgrowth from the thalamencephalon. The eye does not reach the surface, but * This section is limited to papers which, while relating to Vertebrata, have a direct or indirect bearing on Invertebrata also. + Nature, xxxiv. (1886) pp. 33-5 (2 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581 is imbedded in connective tissue, so deeply indeed as almost to preclude the idea of its being affected by light. In a postscript Mr. Spencer adds that he has since found the eye in Iguana, Chameleo vulgaris, and Lacerta ocellata, and has traced the nerve into the proximal part of the epiphysis. Probable Cause of some Monstrosities.*—Dr. H. Cutler suggests that abnormal forms of spermatozoa are sometimes the cause of teratological conditions in the children, and states that abnormal forms of the following character have been observed in the sperm of man: spermatozoa with two or three bodies, with one body and two or three tails, with two bodies and two tails, and two bodies and three tails. The average proportion of these monstrous spermatozoa is almost 1 in 50,000; their movements are slower, but more vigorous than those of normal forms. In examining the urine for abnormal Spermatozoa, it is advisable to make use of a cell 2} by 3/4 by 1/16 inch, and a dry 1/4 inch objective with a long working distance. Origin of the Deep-sea Fauna in the Sub-alpine Lakes.t—Three explanations have been offered of the origin and ancestors of the deep- sea fauna of these lakes: according to Prof. A. Forel only one is of practical value. The theory that this fauna is derived from old deep- sea fauna of the tertiary period is inadmissible, for the glacial epoch would have destroyed that fauna, although, it is true, certain organisms, e.g. Desoria glacialis, the ice flea, and Protococcus nivalis, flourish in ice; moreover, the existing fauna is of quaternary origin. The sur- rounding mountains, which stood above the covering of ice, may have supported life, but this would have nothing in common with the deep- lake fauna. According to the author, this fauna arose partly from voluntary and partly from involuntary migration from lake to lake. When the glacial period ended, as the ice gradually retreated up the valleys, animals and plants, which had been driven into neighbouring regions, would wander back ; but this would only apply to river or land fauna, since deep-lake fauna require special adaptations. The pelagic fauna might arise by small littoral animals being carried by currents to the centre of the lake, and there, by natural selection, their descendants might become transparent and otherwise modified for a pelagic existence. But the bottoms of lakes are completely separated from one another ; and even to rise to the surface would be impossible to most of the animals adapted to a deep-lake existence. According to Forel the only explanation is that this particular fauna is derived from the littoral fauna, since a large number of species is found to be common to both fauna, and some are common to the cave fauna. By a voluntary migration it is supposed that littoral animals have wandered from the shore, have become bewildered, and in their efforts to return, got further and further from the shore, and therefore in deeper and deeper water; they thus lose their way, and have to remain where they are; their eyes are of little use to them, since for sight they require a bright light, which is, of course, absent in the depths. * Medical World, iv. (1886) pp. 18-20. + N. Denk. Schweizer. Gesell. f. d. Ges. Naturwiss., xxix. (1885) 234 pp. Cf. Naturforscher, xix, (1886) pp. 191-3. 582 SUMMARY OF CURRENT RESEARCHES RELATING TO By an involuntary migration, animals are carried away by fish, e. g. as eggs, or as fish parasites, &e. Though rare, landslips on the shore may be a means which should be considered. Ebb tides carry mud from the littoral zone, and with this mud eggs and small animals. Lastly, animals and eggs fix themselves to pieces of wood, &c., which float away from shore, become waterlogged and sink, and the animals may in this way become naturalized to a deep-sea life. If these small causes, occurring year after year, be considered in the aggregate, voluntary and involuntary migrations will probably be sufficient to explain the origin of this deep-lake fauna. B. INVERTEBRATA. Horizontal and Vertical Geographical Distribution of the Pelagic Fauna of Fresh-water Lakes.*—Dr. O. E. Imhof finds that some species of Copepoda, Cladocera, Rotatoria, and Protozoa are ubiquitous, while others are limited to very definite areas. This, which is par- ticularly true of horizontal distribution, applies also to the vertical ; Anurza longispina is the most widely distributed vertically, while other species are found only at certain depths. Endothelium of the Internal Wall of Vessels of Invertebrates. —M. W. Vignal finds that the vessels of invertebrates have an epi- thelial layer which presents the same characters as the endothelium of the lymphatics of vertebrates, and that the vessels of invertebrates open into the interstices of the connective fibres, where, as we know, Bichat and Ranvier place the origin of the lymphatics of vertebrates ; this mode of origin is, in the author's opinion, more than probable, although it has not been absolutely proved in consequence of the obstacles to injections which are presented by the valves of the lymphatic trunks. M. Vignal reminds us that Prof. Sabatier has noted the existence of an endothelium on the internal surface of the vessels of the mussel, but he has figured it as resembling a blood endothelium, while the stomata which he figures are, as Afferow has demonstrated, due to imperfect impregnation ; nor are they nuclei, as Sabatier supposes. Blood of Limulus, Callinectes, and a Holothurian.t—Dr. W. H. Howell thinks that there is no good reason why there should not exist to a certain extent, in closely allied animals having the same general habits of life, a fundamental similarity in the chemical constitution of the blood. An albumen may still be present in the blood of an animal, as a remnant of a previous mode of life, although now no longer useful; and in this way the study of the blood may be a useful indication of the true affinities of the animal. By the study of the coagulation of the blood in the lower animals, since it is probably simpler than in vertebrates, a better understanding of the phenomena in mammalian blood may be obtained. * Zool. Anzeig., ix. (1886) pp. 335-8. + Comptes Rendus, cii. (1886) pp. 1027-8. { Stud. Biol. Laborat. Johns-Hopkins Univ., tii. (1886) pp. 267-87 (1 pl.). See also this Journal, antec, p. 68. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 583 Limulus is a convenient animal in which to study coagulation, on account of the great quantity of blood contained. On exposure to air it coagulates, though not firmly, in a few minutes. Dr. Howell was unable to prevent coagulation by saturation with magnesium sulphate, which Halliburton found possible. Four different albumens were found, coagulating at 60° C., 70° C., 75° C., and 80° C. The last is especially difficult to precipitate completely. The author differs from Halliburton in regarding the name hemocyanin as more applicable to this last albumen. From the various experiments on the serum the author concludes that the albumens of Limulus serum belong to the globulin group, and though not identical with para- globulin, it is to it that they approach most nearly. Hzeemocyanin, 2 combination of copper with proteid, gives no absorption bands, though it cuts off a large portion of the blue rays. When oxygen is excluded it loses colour; this is well seen in the blood of Crustacea ; but in Limulus the result is not so evident; the respiratory process , seems less marked. The loss of colour only commences when the last albumen begins to be thrown down. Coagulation is caused by the union of processes sent out by the corpuscles; these processes shorten and draw the corpuscles closer together. The fibrin thus formed resembles that of mammalian blood, by its solubility in 10 per cent. magnesium sulphate. In Callinectes the coagulation of the blood when drawn is much less rapid than in Limulus ; moreover a firm jelly is formed. There are only two albumens, coagulating at 55° C. and 68° C., the latter of which is hemocyanin. The blue colour of the blood disappears on the passage of CO, ; and the author considers, from various experi- ments, that the hemocyanin in the two animals isa different substance. The albumens appear to be globulins. The coagulation arises in the same general way as in Limulus, but the fibrin produced has different properties. Dr. Howell concludes from the examination of the blood in these two animals that “the differences are too wide to permit us to suppose any close relationship between the two forms;” but observations on the blood of arachnids are necessary before concluding anything as to the relation of Limulus to them. In the perivisceral fluid of a Holothurian—Thyonella—oval, nucleated, heemoglobinous corpuscles are found, as well as colourless amoeboid corpuscles. These corpuscles sink and form a sort of incipient coagulation, caused by the fusion of thick pseudopodia of the white corpuscles, as well as of the corpuscles themselves; the red corpuscles do not fuse, but may get entrapped in the mass. No albumens were found in this serum. Mollusca. Embryology of Gastropods.*—Mr. J. P. MacMurrich gives a preliminary account of his work on the development of some marine Prosobranchs. Out of the numerous eggs deposited by Fasciolaria tulipa, in each * Johns-Hopkins Uniy. Cire., v. (1886) pp. 85-6. 584 SUMMARY OF CURRENT RESEARCHES RELATING TO capsule only six or eight develope. In the case of Purpura floridana a certain number of ova, after undergoing segmentation, break down and are used as food by the surviving ova. In Neritina only one egg, out of a number in each capsule, segments and comes to maturity. The eggs of Fulgur carica are large and contain much yolk: a single large polar body is formed. After dividing into two and then four equal spheres, four protoplasmic micromeres are separated off from the macromeres ; then four more micromeres are formed, and they continue to divide. This process of micromere- separation goes on till the macromeres are covered ; and even after the blastopore has closed, new micromeres are formed, which give rise to mesoderm: thus this layer is not due entirely to a large primitive “ mesoblast ” as in Nassa. The stomodeum is formed on the area of closure of the blastopore. The development of the endoderm was not satisfactorily made out. The author holds that this method of segmentation is essentially the same as that in Hirudinea, Gephyrea, Turbellaria, &c., and that all have been derived from forms which had a typical segmentation, such as that seen in Pul- monata and many other Gastropods; other forms in each group having departed from their original mode by the subsequent loss or addition of yolk. Thus, the regular segmentation so frequently occurring is not primitive, but has been secondarily induced by absence of yolk. In Lamellibranchs, Pteropods, and Heteropods, the formation of the supracesophageal ganglion agrees with that in the typical trochosphere larva of Polygordius. In marine Prosobranchs, how- ever, these ganglia arise as independent ectodermal thickenings, which become later on united to one another and to the pedal ganglia. The apical thickening in the trochosphere larva, from which the supracesophageal ganglion is formed, is represented in others by the problematic cells, regarded by Wolfson as a nervous organ; but the ganglion is not, in these forms, formed from these cells. The prosobranch veliger is very highly specialized, and affords an excel- lent instance of larval specialization, independent of specialization of the adult. Nervous System and Organization of Scutibranch Gastropoda.* —M. E. L. Bouvier unites under the head of Scutibranch Gastropods a number of molluscs which have been placed with the Cyclobranchiata and the Aspidobranchiata; they are united by the following characters :-— 1. The cerebroid commissure is very long, so that the ganglia are set at the sides of the digestive tube; these ganglia are pro- duced forwards and below to form a strong ganglionic projection, which is united with that of the opposite side by a subcesophageal commissure ; this cord is called the proboscidial commissure. 2. The stomato-gastric system arises from the inferior point of the proboscidian projection, and forms a loop; the two sympathetic ganglia are generally widely separated. 3. The pedal ganglia are well developed and form pedal cords, * Comptes Rendus, cii. (1886) pp. 1177-80. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 585 while the principal nerves with which they are continuous are almost always united by transverse commissures. 4. The pallial ganglia are always more or less intimately con- nected with the pedal ganglia. The two first of these sets of characters are regarded as being primitive in nature. Some of the facts here brought forward are in opposition to the statements of M. Bela Haller, who denies the presence of the proboscidian commissure described by Lacaze- Duthiers in Haliotis tuberculata. M. Bouvier is able to support the statement of the French anatomist on this and other points traversed by M. Haller. Retina of Helix pomatia.*—In a further communication on the structure of the optic organ, Prof. J. Carriére describes the retina of this common snail. The method of examination employed was to cut off the tip of the tentacle with the eye, to expose it for a few minutes to the vapour of 1 per cent. osmic acid, and colour with -picrocarmine. The removal of the pigment was effected by very dilute eau de Javelle, but this is an operation which must be performed with great care. Sections of about 0-005 mm. thickness were made. The colourless cells were found to be flask-shaped, and to have contents which were not stained either by picrocarmine or by hematoxylin, but with osmic acid hardened to a clear grey mass which completely filled the cell, and rose above it as a convex swelling. No differentiation was to be noticed within the mass; when the convex boundary was distinct, the cell was divisible into a retina and hardened lens, but in other cases the cell-contents ap- peared to pass directly into the lens. The colourless cells are not regularly polygonal but intercalated among the pigmented, so that they present all stages between an irregular polygon and a star; their lateral processes entered as far as the pigmented cells. The pigmented cells are not filled with pigment, a narrow axial cord being free from it; when the pigment is removed the cells are scen, on staining with picrocarmine, to have a homogeneous transparent grey cell-body, which is very different to the reddish~yellow contents of the flask-shaped cells; there is a highly refractive axis which corresponds to the bright spot seen in pigmented cells, from which the colour has not been removed. In some points the author differs from the results recently published by Hilger. Organization of Phenicurus.—Dr. R. 8. Bergh f has addressed a letter to Prof. H. de Lacaze-Duthiers in which he expresses his opinion that Phenicurus is really a papilla of Tethys; he bases this view on what he has himself been able to observe at Naples. The Professor, in an extended essay,{ adds to our knowledge of this form, on which he has already published a note §; in answer to his critic he points out that no figure has ever been published by him or by those who think with him, and reminds us that Dujardin stated in 1845 that * Zool. Anzeig., ix. (1886) pp. 220-3. t Arch. Zool. Exper. ct Gén., iv. (1886) pp. 73-6. t Tom. cit., pp. 77-108 (2 pls.). § See this Journal, v. (1885) p. 1005. 586 SUMMARY OF CURRENT RESEARCHES RELATING TO several naturalists had confounded the appendages of certain molluscs with the true Phenicurus ; as to the hepatic trunk spoken of by Bergh, it is not the dendroccelous digestive tube of Phenicurus for that has no resemblance to a hepatic appendage ; the so-called mouth is really the external circulatory orifice; this question is entered into in great detail. At the end of a number of arguments forcibly put M. de Lacaze-Duthiers pertinently asks what can be the use to the Tethys of such large appendages which fall off so easily ? Pericardial Gland of Lamellibranchs and Gastropods.*—Prof. C. Grobben, who has already shown that the so-called branchio- cardiac appendage of the Cephalopoda is a glandular structure, now extends his observation to other classes of the Mollusca. In the Lamellibranchiata the pericardial gland has either the form of glandular lobes or of cca, which are developed from the peri- cardiac epithelium, and lie in the anterior angle of the pericardiac space. The lobes are found in Arca, Mytilus, Pecten, and Ostrea ; the lobes in Unio, Venus, and Scrobicularia, but they differ con- siderably in their grade of development. The epithelial cells which form the gland contain concretions of various forms and sizes. Among Gastropods a similar organ is to be observed in Fissurella, Parmophorus, Haliotis, Turbo, and Trochus. The function of the gland appears to be excretory, and to be allied to the renal; the products probably escape into the kidney, whither they are driven by its ciliated infundibula. The glands appear to have a general homology with those already described in Cephalopods ; their presence in the last-mentioned group leads the author to believe that the Cephalopoda represent a branch of the molluscan phylum which very early became independent of the rest. Pedal Gland and Aquiferous Pores in Lamellibranchs.t — Dr. T. Barrois has studied in sixty species the glands of the foot and the aquiferous pores of Lamellibranchs ; the differences which obtain in the different families are described, and the conclusion is arrived at that the byssus is peculiar to the group, and is secreted by glands which are homologous with the pedal glands of Gastropods; various stages of degradation are to be seen in various families. The ex- amination of the intercellular canals and aquiferous pores, which are in some forms completely wanting, has shown that the so-called aquiferous pores are really the orifices of the byssogenous glands, and that there is no direct communication between the circulatory appa- ratus and the exterior ; there is, in fact, no mixture of blood and water. Eyes of Pecten.{—Referring to Hickson’s theory that the “eye” on the mantle of Pecten serves to warn the animal of the ebbing tide, by reason of its being affected by the growing intensity of the light, Prof. B. Sharp has reason to think that this “eye” is an organ not for admission but for emission of light; that is, that it is the organ whence the phosphorescence observed in this mollusc is derived. * Zool. Anzeig., ix. (1886) pp. 369-71. + Pp.170,8 pls. 4to, Lille, 1885. Cf. Journ. de Microgr., x. (1886) pp. 93-0. t Proc. Acad. Nat. Sci. Philad., 1886, pp. 61-2. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 587 Poison of the Edible Mussel.*—-Dr. G. Baumert reports that on examination the poison of the mussel was found by Herr E. Salkowski in a cold alcoholic extract of the substance of the mollusc ; watery extracts were also poisonous ; these results were obtained by physio- logical experiments. The chemical investigation of Herr Brieger showed that there was a non-poisonous base, the specific mussel-poison, an extremely poisonous substance which produced a copious flow of saliva and diarrhcea, but was not mortal, and a decomposition-product of poisonous properties. The mussel-poison appears to belong to the group of ptomaines, and is therefore a decomposition-product of the flesh of the mussel. Dr. Schneidemiihl is of opinion that the liver is the seat of the poison, therein agreeing with Salkowski. Molluscoida. a, Tunicata. Phylogeny of the Tunicata.t—Prof. W. A. Herdman, referring - to the views expressed by Dr. Uljanin in his monograph on Doliolum, agrees to the suggestion that the Appendiculariide gave rise to other Ascidians, but doubts the origin of the Salpide and the Doliolide from groups of the simple Ascidians; he thinks it unlikely that the Thaliaceee were ever fixed simple Ascidians. He would regard the simple and compound Ascidians as being derived from a common ancestor resembling the simpler forms of the two groups, in preference to supposing that the compound were derived from the simple; many of the latter show far more differentiation and specialization of certain important organs (e.g. the branchial sac in the Molgulide) than is found in any of the compound forms. He protests against Uljanin’s view, that the social are derived from the compound and have no close connection with the simple Ascidians ; for there is a very close relationship between the Clavelinide and the Ascidiide, and the “social” group seems to be distinctly intermediate between the least modified form of the two other groups. Pyrosoma, it is agreed, is a modified compound Ascidian, but Prof. Herdman thinks it is derived from the Didemnide and not from Distaplia ; this last is not as ex- traordinary a form as is generally supposed. The compound Ascidians appear to have had a polyphyletic origin. B. Polyzoa. Researches on Blastogenesis.{—M. L. Joliet, in discussing the gemmation of marine ectoproctons Bryozoa, deals particularly with the criticisms on his previous work which have been made by Prof. Haddon and Dr. Vigelius. He comes to the conclusion that there is only a single homogeneous tissue—the apical endocyst—at the vege- tative end of a stolon or cell of a gymnolematous form; this is neither ectodermal nor endodermal, but is an indifferent tissue. In some species no other tissue than the parietal endocyst, from which the polypide and the sexual are formed, is to be found; in most, * Zeitschr. f. Naturwiss., lix. (1886) pp. 60-2, + Nature, xxxiii. (1886) pp. 546-7. t~ Arch. Zool. Exper. et Gen, iv. (1886) pp. 37-72 @ pls.). 588 SUMMARY OF CURRENT RESEARCHES RELATING TO however, the apical endocyst becomes differentiated into two systems of tissues—the parietal endocyst, which continues to form and thicken and gradually loses its vital structure and activities, and the endosare, or central endocyst (or funicular tissue, &c.), which takes on a special structure varying with different species, but always preserves its vital activity and remains an indifferent tissue. As soon as the homogeneous tissue which forms the polypide has become differentiated into two layers, there is an ectodermal tissue enclosed in a pouch which is at once endoderm and mesoderm. This tissue undergoes a fresh differentia- tion, for in its centre a small mass of cells which will form the intes- tine become isolated. Henceforward the individual bryozoon is con- stituted, and so far the author agrees with Vigelius, Haddon, and Barrois. Before the appearance of the polypide in the zocecium the latter has only contained an indifferent tissue ; after its appearance all is changed, and a number of organs appear. The tentacles with their flagellate epithelial cells, and the epithelium of the lophophore and of the cesophagus no doubt represent the ectoderm. The tentacular sheath consists internally of muscular fibres, and externally of a layer of delicate flattened cells, which appear to be ectodermal. The parietal endocyst, differentiated and specialized as it is in Flustra, may be regarded as forming an outer skin, or somewhat more definite ecto- derm. All the parts in the zocecium, which are contained between the outer skin and the intestinal epithelium with the internal epithe- lium of the tentacular sheath form the mesoderm and the general cavity. In a future work the author hopes to show that in Endoprocta and Lophopoda the endocyst and endosare take on the special cha- racters of an ectoderm and a meso-endoderm; that the archenteron arises in the midst of this latter ; that the lophophore, cesophagus, and rectum are directly produced by the ectoderm; and that in all Bryozoa the polypide is constituted and developed along a general uniform and common plan. Development of Cyclostomatous Marine Bryozoa.*—Herr A. Ostroumoff finds that the larve of the Cyclostomata are the most simply organized of the marine Bryozoa; their whole surface is covered with cilia; at one pole there is a sucker, and at the other the mantle- cavity. The endodermal cavity disappears before the larve escape ; there is no velum, and no other provisional organs are developed. As in other larve, metamorphosis commences with the protrusion of the sucker which forms the basal wall of the primary zocecium, and with the overlying of the basal surface by the mantle. The broadening basal wall gives offa special kind of stolo prolifer, the “lame germinale” of d’Orbigny. The ectodermal rudiment of the polypide is formed from a plate which is delaminated from the ectodermal cells at the point where, in other larve, the velum is developed. This plate then bends basalwards and becomes invested by mesodermal cells. The so-called “lame germinale” is homo- logous with the stolo prolifer of the Vesicularide, and the groups Incrustata and Stolonifera connect therefore the two orders, Cyclostomata and Ctenostomata. * Zool. Anzeig., ix. (1886) pp. 283-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 589 Arthropoda. Affinities, Origin, and Classification of Arthropoda.*—Dr. A. C. Oudemans is of opinion that the group Arthropoda ought to be given up; in support of this proposal he discusses seriatim a number of the sub-groups of which the larger group is at present supposed to consist. 1. The Acaroidea appear to be a special group, which ought to be separated from the Arachnoidea. 2. The Tardigrada appear to be more closely allied to the Cheetopoda than to either the Arachnoidea or Acaroidea. 3. The relations of the Scorpions, Trilobites and King-Crabs, may be indicated by the subjoined table :— Prestwichia Limulus Scorpio | Pterygotus Belinurus | Slimonia Neolimulus / : Hemiaspis Wa Xiphosura Bunodes vi Eurypterus WA Ee j re Eurypterida ve Phacops Agnostus Trilobita N | Proagnostus | 4, The Crustacea, after the removal of heterogeneous forms, are a natural group, whose primitive larva is the Nauplius, which is very different to the primitive larva of the Arachnoidea—Proagnostus. 5. Dohrn has completely proved the absolutely separate position of the Pantopoda. 6. The Onychora (Peripatus) are also very distinct ; their develop- ment shows that they come from animals like the Gastrula with a * Tijdschrift Nederl. Dierk, Vereen., i. (1886) pp. 37-56. 590 SUMMARY OF CURRENT RESEARCHES RELATING TO nerve-ring round the blastopore ; it is quite possible that this branch is much younger than that of insects. 7. Embryology does not yet enable us to say definitely whether the Hexapoda and Myriopoda form a natural group, but the evidence of anatomy is in favour of their being so; the difficulties presented by the Chilognatha are not yet solved. The Hexapoda must have branched off early from the common stem. At present the two sets may be kept together under the name of Insecta ; as for the rest, they are best compared & posteriori, and not @ priori. Embryology of Insects and Arachnids.*—The embryology of Arachnids shows many resemblances to that of insects. Mr. A. T. Bruce has traced the development of Thyridopterya ephemereformis from early segmentation to an advanced embryonic stage. In the earliest stages cells are found in the yolk, whence they emigrate to form a blastoderm; the egg therefore is not truly centrolecithal. Some of these cells never reach the surface, but remain as “ yolk bulbs.” In the grasshopper all the cells emigrate, and the yolk is arranged in pyramidal masses. The embryo in insects is formed from a thickening of the surface of the egg, like the primitive annulus of spiders. The endoderm and mesoderm arise partly by invagination and partly by delamination along the middle line; the yolk-cells appear to have nothing to do with the formation of endoderm. No “dorsal organ” like that described by Brandt in the Neuroptera, was observed in the insects studied—including Lepidoptera, Coleoptera, and Orthoptera. The nervous system arises as two ectodermic strings at the sides of the blastopore. The supra-cesophageal ganglion in Thyridopteryx consists of two parts, the posterior of which supphes the paired labrum, the anterior, the antenne. In the grasshopper both maxille have two lobes at the base of the main axis, recalling the exopodite and epipodite of crustacean appendages, though they are probably not homologous. In one stage of the spider embryo an abdominal appendage is being converted by invagination into a lung-book. The amnion in Thyridopteryx forms part of the dorsal surface of the body. Tracheal invaginations occur in the maxillary segments of the grasshopper. a, Insecta. Spermatogenesis.|—Continuing his classical researches on sper- matogenesis, Prof. v. la Valette St. George describes the development of the sperms in Blatta germanica. 'The male glands, which have the form of four transparent vesicles lying in the last segment, and provided with a fine efferent duct, are surrounded by white fatty * Johns-Hopkins Univ. Cire., v. (1886) p. 83. t Arch. f. Mikr. Anat., xxvii. (1886) pp. 1-12 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 591 bodies, by a structureless tunica adventiva, and by a nucleated tunica propria, which with its internal prolongations divides the gland into spherical segments. The spermatocysts within, surrounded by a nucleated envelope, contain the spermatocytes, and resulting sperma- tides. The investigation of the development of the spermatocytes, preserved in an indifferent fluid, was best achieved by staining with dahlia. The nucleolus both in spermatocyte and spermatide is described as a thickened inward projection of the nuclear membrane. The nuclear metamorphosis of the probably three successive generations of spermatocytes is described in some detail, and in essential agreement with the accounts of similar processes given by Biitschli and Mayzel. The origin of the accessory nuclear body from the cytomicrosomata in the spermatocytes, and of these from remnants of the spindle-fibres is described. As in his previous communications, v. la Valette St. George refers the transitory head of the sperm to the nucleus of the spermatide, the tail to the proto- plasm, and the middle portion to the accessory body or “ Nebenkern.” Germinal Layers in Hydrophilus.*—-Dr. K. Heider has communi- cated some of the results of his studies on the development of Hydro- philus in an account of the formation of the germinal layers. After describing the general characters of the ovum, he notes (a) the appearance, multiplication, and migration outwards of the cellular corpuscles which form the future cells of the blastoderm. These reach the superficial plasma layer, first at the posterior pole, where they become defined into cubical-rounded cells. (b) The next change is the formation of the ventral plate as a somewhat thicker, slightly arched layer, which becomes marked off by longitudinal furrows and slightly projecting lateral walls, to form the endoderm and mesoderm plate described by Kowalevsky. The furrows becoming deeper, unite anteriorly and independently posteriorly, and the whole plate is somewhat sunk below the level of the ectoderm. (c) This is followed by the insinking of the plate, and its curvature into a median canal which becomes grown over by the ectodermic margins. The margins of the furrow-like invagination represent the blastopore, and it is interesting to note that the very anterior portion is the last to be closed, persisting as a distinct aperture in the future position of the cesophageal invagination which occurs at a much later stage. The future closure of this region, and the details of the general invagina- tion, the subsequent broadening and flattening of the tube, as if by dorso-ventral compression, and the appearance of the lumen at various stages till its final disappearance, are then described in detail. When (d) the furrow has been completely closed, and when the embryonic envelopes have completely arched over the embryo, Kowa- levsky’s second period of development begins,—the period of the differentiation of endoderm and mesoderm, and of the appearance of the organs. On the ectoderm, on both sides of the middle line, the first hint of the nervous system is seen as a slight thickening. The compressed tube, with its all but wholly obliterated lumen, * Abh. K. Preuss. Akad. Wiss. Berlin, 1885, pp. 1-47 (2 pls.). 592 SUMMARY OF CURRENT RESEARCHES RELATING TO becomes differentiated into a two-layered endo-mesoderm. The boundary between the external layer next the ectoderm and the internal layer next the yolk represents the compressed lumen of the primitive tube, i.e. the primitive enteric cavity of the modified gas- trulation. The histological differentiation of the two layers is dis- cussed in detail, and Dr. Heider shows how from the external, the somatic mesoderm arises, and from the inner, the endoderm and mus- cular lining of the alimentary canal. (e) The boundary between the outer and inner layer enlarges on either side to form clefts which increase in width and form the primitive cavities of the segments. The lateral portion of the inner layer which thus bounds these clefts forms, for the most part, the muscular layer of the mid-gut, while the median portion, becoming histologically differentiated, forms the epithelial layer of the same, becomes in fact the final endoderm layer. (f) The body-cavity, formed independently of the primitive segment cavities, appears as a cavity between the yolk and the somatic meso- derm layer. The details of these processes, and of others, such as the growth of the ectoderm round the yolk, are noted. It is interest- ing to note that just as the anterior and posterior defining of the furrow-like invagination originated independently, so the endoderm layer is formed in two separate anterior and posterior portions which subsequently grow together across the intervening gap. Dr. Heider describes (g) the condition of the yolk with persisting cellular bodies, and with cells which wander inwards from the endo- mesoderm, and emphatically denies the frequently asserted formation of part of the internal layer from the apposition of nuclei from the yolk. The degeneration of the latter, and its absorption by pseudo- podia-like processes from the endoderm cells is noted. While agree- ing with Kowalevsky, as against numerous other investigators whose views he criticizes, as to the origin of the endoderm from the invagi- nated lower layer, Dr. Heider differs from him on two chief points-— the origin of the primitive segment cavities and the mode in which the endoderm is separated off. For while Kowalevsky derives the former from internal and inferior foldings of the endo-mesoderm, and represents the folded portion as consisting of both endo- and mesoderm afterwards separated, Dr. Heider has described the origin of the cavities from a lateral split between the two layers of the invaginated compressed tube, and derives the endoderm from the median portion between them. This median portion afterwards grows in between the splanchnic mesoderm and the surface of the yolk, which then becomes enclosed dorsally and ventrally by the simple extensions of the two layers. As subsidiary results of his research, Dr. Heider notes (h) that not only on the first abdominal segment, but on all the others rudi- mentary appendages can be observed ; (7) that the transverse com- missure of the ganglionic chain originates by the invagination between the lateral strands of a median portion retaining an intersegmental connection with the ectoderm, that the cesophageal commissure is formed from the anterior portion of the lateral cords without assistance from the mandibular ganglion, that the apical plates are ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 593 from the first in connection with the lateral cords, that the frontal ganglion is formed from an unpaired invagination independent of that which gives rise to the central nervous system; (j) that the dorsal canal described by Kowalevsky is an involution of the egg- membranes ; (k) that the Malpighian vessels arise from the ectoderm as diverticula of the hind-gut. The latter portion of Dr. Heider’s memoir is occupied (1) with a lucid exposition of the opinion that the various germinal layers are derivable from the blastoderm which is superficially budded off from the giant multinuclear trophodic yolk-cell, which thus occupies the segmentation cavity. The gastrulation has the modified form of a long furrow, the boundary between the two layers of the endo- mesoderm represents the primitive enteric cavity, the margins of the invagination form the stretched-out blastopore. The persistence of nuclei within the yolk after the plastic elements have been differ- entiated, may be connected with the delayed absorption of the former. While regarding the yolk as the passive trophodic remnant -comparable to that occupying the centre of a centrolecithally segmented ovum, the author does not exclude the possibility of its phylogenetic origin from modified endoderm segmentation masses, as suggested by Kowalevsky’s report of what occurs in Huawes. Behaviour of Dorsal Vessel during Metamorphosis.*—Prof. A. Kowalevsky has studied in the larve of Muscidx the behaviour of the dorsal blood-vessel during the metamorphosis of the larva. In feed- ing the larve, for another purpose, with cochineal, silver salts, and other colouring matters, he found that the pigment was passed in an apparently uncoloured combination to special cells lying round the heart, viz. (a) to the thirteen pairs of large cells lying posteriorly, (b) to the band-like masses which surround it medianly, and (c) to the anterior “ garland-like strands” described by Weismann. Within these cells the pigment, passed doubtless from the heart by the blood, seems to enter into an insoluble combination with the plasma round about the nucleus. Prof. Kowalevsky is therefore inclined to attribute to these cells a blood-purifying function. The “ garland-like strands” persist unchanged for two days after metamorphosis, a fragmentation of the nucleus sets in, and the cells gradually fall a prey to the fagocytes or granular spheres within which the pigment again forms an uncoloured combination. The strands therefore form an altogether embryonic or larval gland, which does not pass on into the insect. He has shown that the anterior and median portions of the heart completely pass over to the imago, and the cells enveloping the middle portion also persist, changing their position, however, and forming a broad mass of cells, which envelopes the anterior wall of the abdomen as a thick network. They retain their introduced pigment, and even in the adult insect these cells about the median portion of the heart may be artificially fed with colour in similar fashion. * Biol. Centralbl., vi. (1886) pp. 74-9. Ser. 2.—Vor, VI. 2R 594 SUMMARY OF CURRENT RESEARCHES RELATING TO Of the thirteen pairs of large cells at the hinder end of the heart, the six posterior pairs, and probably the portion of the heart between them, fall victims to the voracity of the granular cells; but the seven anterior pairs persist. Prof. Kowalevsky draws attention finally to the important shifting of the heart from its deep position between the tracheal stems in the larval, to its subsequent superficial position just below the external epithelium. Structure of the Honey-Bee’s Cell.*—Herr K. Miillenhoff reports the results of his studies as to the influences resulting in the formation of the honey-bee’s cell. Extending the old observation as to the optimum exhibited by the form of the cell, he shows how its length is also in perfect accord with the best solution of the bee’s problem. As to mechanical explanation, he extends Buffon’s experiment with the boiled bottled peas swollen into hexagonal form by mutual pressure, by showing that the general resultant figures are really rhombododecahedra, while those at the sides exhibit the exact form of the bee’s cell. After referring to Darwin’s, for the most part teleo- logical attempt at solution, he directs attention to the necessity of considering the nature of the component substance, the behaviour of the bees, and the exact nature of the mechanical forces at work. This he has elsewhere discussed in detail.t He emphasizes the perfectly plastic character of the wax at the temperature of comb-building (27°-37° C.), and distinguishes three different phases in the process:—(1) The formation of Maraldi’s pyramids and short prisms, (2) the increase of the prisms to their full length, (3) the filling and closure of the cells. Describing the beginning of the process, he shows how the simple contractility of the material effects the disposition of the wax into small pellicles of equal strength, the perfect squaring of the walls, and the formation of surface angles of 120°. In describing the successive stages, he lays special stress on the variations which must follow the changes of temperature and the continued plasticity of the cell, which is con- tinually tending to acquire smaller surface and stronger walls. The cells behave mutually like soap-bubbles. Maraldi’s pyramids are literally Plateau’s equilibrium figures—with the smallest surface within given limits, and the whole cells are isoperimetric figures— with smallest surface for given content. In short, not to any artistic dexterity on the part of the bee, nor to any direct effect of its body- form, but to “statical pressure according to the laws of equilibrium” is the beautiful result to be referred. Storing and Preservation of Honey.{—Herr K. Miillenhoff, continuing his studies of bees, has investigated the behaviour of the insect in gathering and storing the honey. He discusses the damping and the compression of the pollen, the marvellous adroitness of the bee in forcing its way into flowers, the careful avoidance of mixing the kind of pollen during one gathering, the renewed salivating and * Arch. f. Anat. u. Physiol.—Physiol. Abtheil., 1886, pp. 371-5. + Pfliger’s Arch. f. d. Gesammt. Physiol., xxxii. (1883) pp. 589-618. ¢ Arch. f. Anat. u. Physiol.— Physiol. Abtheil., 1886, pp. 382-6. ZOCLOGY AND BOTANY, MICROSCOPY, ETC. 595 compression which the pollen receives from the younger indoor workers before it is stored in the cells, which are always the cells of workers and not of drones. The pollen is frequently deposited in layers, and frequently hermetically sealed with honey, over which a thin pellicle, like a layer of cream on milk, is formed, and this can be pushed aside for the deposition of mere honey or walked over without causing overfiow. The bees which are going up and down over the full cells often exhibit protruded stings, and that in normal circumstances. Drops of poison from the end ef the sting are seen to be deposited on the honey, and the presence of formic acid, absent in pure nectar, is thus explained. The acid doubtless exerts an antiseptic influence on the honey, and the author has beautifully shown that in uncovered honey- celis none is present, and that fermentation soon sets in, which could, however, be prevented by the addition of 1/10 per cent. formic acid. Herr Millenhoff suggests the possible expediency of removing the honey from the uncovered cells, and thus economizing the time and energy of the bees, while the honey could be readily and cheaply preserved by the addition of 1/10 per cent. formic acid from a pipette. Palps of Mandibulate Insects.*—Prof. F. Plateau has observed fifty individuals belonging to various species of Coleoptera and Orthoptera, and he concludes that during manducation the labial and maxillary palps of mandibulate insects are inactive ; the removal of the maxillary palps does not prevent them from eating in a normal manner, and the same is true of the loss of the labial palps. The amputation of the four palps does not abolish the sense of smell, nor destroy the power of the insects to recognize and seize their food. In fact, notwithstanding the loss of the four palps these insects eat in a perfectly normal manner. It will be noticed that the results of M. Plateau are altogether opposed to the views ordinarily held by entomologists as to the function of the palps. Minute Structure of the Eyes of Diptera.t—The first part of Prof. G. O. Ciaccio’s work consists of sixteen chapters, which treat of the eye of insects generally, of the methods of study, and of a de- scription of the constituent parts of the eye. The second, in thirteen chapters, is devoted to the peculiarities of a number of families, among which are the A‘stride, Syrphide, Muscide, Tabanide, Tipulide, and Pulicide. The third part is divided into five chapters and treats of simple and compound eyes and their relations to one another, and to those of vertebrates, and lastly, of the physiology of vision. Luminous Elateride.{—M. R. Dubois is of opinion that any generalization on the subject of biological luminosity is premature ; for the present we must try and collect as large a number of facts as possible. The luminous Elateride are the animals which best lend * Bull. Soc. Zool. France, x. (1885) pp. 67-90. + Mem. Accad. Sci. Instit. Bologna, 1885, 28 pp. and 12 pls. t Bull. Soe. Zool. France, xi. (1886) pp. 1-275 (9 pls.). 2R2 596 SUMMARY OF OURRENT RESEARCHES RELATING TO themselves to physiological analysis; they are found between 30° 8. and 30° N. of latitude, and between 40° and 180° of longitude. The emission of light is intimately connected with the accom- plishment of an important physiological function, but in some rare cases there is no luminosity. The position, form, and powers of the luminous organs vary slightly in different species, and a few have no such organs. One of the most brilliant is Pyrophorus noctilucus, which has been especially studied by M. Dubois. In the necessary pre- liminary anatomical study certain corrections were found to be necessary with regard to the situation of the stigmata, the distribu- tion of the trachew, and the relations of the nervous system to the light-producing organs. The organs themselves are composed of a special adipose tissue and of certain accessory organs; histochemical investigation revealed the presence of a body which presents the characters of guanin. Intense histolysis takes place within the photogenous adipose tissue, the changes being provoked or stimulated by the penetration of blood into the luminous organ; this histolytic process is accompanied by the formation, within the photogenic cell, of a vast number of small crystalline agglomerations of special optic properties, and especially remarkable for their double refraction. The presence of blood is not, however, indispensable for the production of light, for the ovum is luminous, even before segmenta- tion, and the adipose photogenic cell, when isolated, exhibits the same property; these facts point to a similarity between the sub- stance of the adipose body and that of the vitellus. The larve, which, hitherto unknown, have been by the author found to resemble those of other Elateridz, are luminous; at first they have but a single luminous organ, but this extends over all the segments, and is localized at the points where histolysis is most active. In the adult insect there are three luminous spots which are so placed as to aid walking, swimming, and flying in obscurity. The muscles of the luminous organs regulate the supply of blood to the photogenic organs, and so have an indirect action on the production of light ; the nerves act through the muscles; the photosensitive reflex action has its seat in the cerebroid ganglia; centrifugal irritation of the ganglia produces the appearance of the light, but this is not the case with centripetal stimulation. Respiration has only an indirect influence on the photogenic function, and this by maintaining the vital conditions of the blood and of the tissues; the nature of the focd has no influence on the production of animal light. The cell (the nonsegmented ovum, or the adipose cell) prepares the photogenic principles under the influence of nutrition, but the light is not the direct result of the proper activity of the organized and living ana- tomical element. When the structure of this anatomical element and its vitality are destroyed the luminous phenomenon can still be pro- duced by a physico-chemical action, similar to that which converts glycogen into sugar in the liver. Though the luminous organs of Pyrophorus are the most remarkable known to us, the organic expense is almost insignificant as compared with the effect produced ; s0, too, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 597 the loss of energy is very slight, whereas in artificial ight it may be as much as 98 per cent. The author analyses the causes of the admirable economic superi- ority, and ascribes it to the following causes :— 1. There are a number of chemical rays in this light as may be shown by photography, but there is only a small proportion of them ; the result must be ascribed to the existence of a fluorescent substance which has been discovered in the blood ef Pyrophorus, and which, by penetrating into the organ, gives it the special and brilliant character which distinguishes the light. The greater number of the chemical rays are transformed into very brilliant fluorescent rays of a medium wave-length. 2. Optie analysis shows that the light is m great part composed of rays similar to those which are found at those points of the spectrum where experience has fixed the maximum of illuminating intensity. 3. There is no loss by heat-radiation ; the amount of heat given off, even at the time of greatest activity, is infinitesimal. 4, There is no reason for supposing that there is any conversion of energy into electricity. 5. This marvellous light is physiological because it is of vital origin, and beeause no other source is as well adapted to the wants of the organ of vision in the animal series. Honey-dew.*—M. Boudier finds the composition of honey-dew from the Aphis of the laburnum to be as follows :—Cane-sugar 57°25 ; inverting sugar 16:25; dextrin, mucilaginous substances, albumi- noids, &e., 26°5 per cent. It frequently contained Mucedinee, which possibly, in their development, have transformed a portion of the cane- sugar into inverting sugar. In damp weather there are developed on the leaves covered with honey-dew large numbers of fungi belong- ing to the genus Cladosporium. B. Myyriopoda. Early Development of Iulus terrestris.;—Mr. F. G. Heathcote experienced considerable difficulty in preparing the ova of Iulus terrestris, owing to the hard chitinous chorion and the great amount of food-yolk. Attempts to remove the chorion by Bobretski’s method were failures; Perenyi’s fluid burst the chorion quickly, but the contents escaped; in the result Mr. Heathcote cut sections of the ova with the chorion still on. The sections were most satisfactorily stained by Grenacher’s alum-carmine. The ovum, when within the ovary, is surrounded by a follicular envelope, has a large nucleus and a single large nucleolus, which stains very deeply. Sections made from ova late on the day of oviposi- * Assoc. Fran. pour l’Avancement des Sci., Congres de Blois, 1884, 8 pp. See Bull. Soc. Bot. France, xxxii. (1885) Rev. Bibl., pp. 122-3, + Quart. Journ. Micr. Sci., xxvi. (1886) pp. 449-69 (2 pls.). Proc. Roy. Soc. Lond., xl. (1886) pp. 73-6. 598 SUMMARY OF CURRENT RESEARCHES RELATING TO tion revealed the nucleus not at the periphery, but in a mass of pro- toplasm in the centre of the ovum; from this mass ameeba-like processes radiate in all directions, and form a protoplasmic network throughout the egg; the nucleus is no longer a distinct vesicle. Early on the second day the nucleus and the central mass of proto- plasm divide into two parts, but the parts remain connected by a network of protoplasm. At the close of segmentation there are a number of masses, each with a dense central portion in which is the nucleus, while the outer portion is broken up into innumerable processes, which cement the masses together and permeate the yolk in every direction. Mr. Heathcote attaches more importance to the connection of layer with layer by means of cell-processes than to the connection of cell with cell. He believes that nothing of the sort has been de- scribed before, but more than ten years ago Prof. Ray Lankester (in vol. xiv. Q. J. M. 8.) directed attention to “an important histo- logical arrangement seen” in a specimen of a developing Lymnzxus, where there was “a connection of the endodermal mass of cells with those forming the body-wall by means of long processes . . . the processes appear to be actual filaments of the cell-substance of the endodermal cells.’ The mesodermal “keel” is formed both by ectoderm and endoderm ; later on, the greater part of the mesoderm becomes arranged in two parallel longitudinal bands along the ventral surface of the embryo, and these bands are connected by a thin bilaminate portion; the mesodermal somites are at first solid, but later a cavity appears in them; the formation of the meso- derm almost exactly resembles that of spiders, as described by Balfour. The nerve-cords are, at an early stage, widely separated from one another, but connected by a thin median portion; later on, they almost form one cord. The lumen of the Malpighian tubes is from the first continuous with that of the proctodeum. The author concludes by comparing his results with those of earlier observers on this and allied forms. y. Prototracheata. Development of the Cape Species of Peripatus.*— Mr. A. Sedgwick enters into fuller details as to the development of Peripatus than in his communication to the Royal Society which we have already noticed.| Notwithstanding the sponge-like structure of the ovum of P. capensis it can hardly be doubted that some not very remote ancestor must have had an ovum heavily charged with food- yolk; in P. nove zealandie the ovum is considerably larger 1:5 x 1mm.) than that of P. capensis, and contains a large amount of food-yolk, while the shell is thick and chitinous. On the other hand, the West Indian species described by Kennel has a small ovum (0°04 mm.); so that we have in P. nove zealandixe with greatest * Quart. Journ. Micr. Sci., xxvi. (1886) pp. 175-212 (3 pls.). jt P + See this Journal, ante, p. 239. . ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 599 length of ovum 1°5, in P. capensis 0°5-0°6 mm., of P. balfouri 0:4-0°5 mm., and of P. edwardsii 0:04 mm., a perfect series in regard to size and amount of yolk. As to the segmentation it is not only to be noted that it is not a true segmentation, but also that no part of the nucleus or centre of force of the unsegmented ovum enters the clear endoderm masses ; when endodermal nuclei do appear, they are larger than the ecto- dermal and are very irregular in shape; dividing directly, they do not exhibit the usual karyokinetic’ figures. In other words, there are two different modes of segmentation, neither of which are instances of complete cleavage in the ordinary acceptation of the term. The first kind is preceded by the division of the nucleus of the fertilized ovum and its products, and this gives rise to the ectoderm cells ; the second, which takes place contemporaneously with the first, divide the larger and cleaner vegetative part of the ovum with the endoderm masses. Inasmuch as the gut is to be looked upon as a vacuole, it resembles in all essential respects the cavity in the body of a ciliated infusorian. After a full account of the nucleus of the unsegmented ovum, the male and female pronuclei and the endodermal nuclei are described in detail; the structure of the gastrula and the formation of the mesoderm are discussed, and, in conclusion, the author extends the results which flow from his discovery of the syncytial nature of Peripatus ; if they are of general truth we must modify our ideas about the ancestral metazoon, and, instead of looking on it as a colonial protozoon, regard it as having the nature of a multinucleated infusorian, with a mouth leading into a central vacuolated mass of protoplasm. In centrolecithal eggs it has already been observed that in early stages separation was incomplete, but the ordinary explanation that this phase is only temporary is not confirmed by Heathcote’s discovery that there is no separation in the myriopod Julus. 6. Arachnida. Development of Agelena uevia.*—After a short review of the comparatively few works on the subject, Mr. W. A. Locy gives an account of his own researches. 1. The eggs.—Eggs in the fresh state were studied when im- mersed in pure oil; external features were also observed on eggs hardened in alcohol, after removing the shell and clarifying with oil of cloves. The most satisfactory method of preparing them for sections is to heat the eggs in water to 80° C., and after being slowly cooled, to pass them through a graduated series of alcohols. Perenyi’s fluid produces an alteration in the yolk, but is useful in conjunction with other methods. Corrosive sublimate renders the eggs too brittle. Grenacher’s borax-carmine is the best staining agent, though in the later stages the egg has to remain in the fluid for a considerable * Bull. Mus. Comp. Zool, Cambridge, xii. (1886) pp. 63-95 (12 pls.). 600 SUMMARY OF CURRENT RESEARCHES RELATING TO time, and in order to prevent maceration it has to be rehardened from time to time. Eggs heated with Perenyi’s fluid gave the most satisfactory sections. The egg when laid is surrounded by a tough chorion (deposited during the passage down the oviduct) which is covered with granules, Within this is a structureless vitelline membrane formed whilst the egg is still in the ovary. In the centre of the egg is the nucleus surrounded by nearly clear protoplasm ; this is connected by protoplasmic strands with a peripheral layer of protoplasm—the blastema—containing numerous oil-globules ; imbedded in the meshes of the protoplasmic network connecting the two layers of protoplasm are numerous large albuminoid yolk-corpuscles. 2. The embryo—The development of the embryo is, for conveni- ence, divided into five periods. The preblastodermic period.—The yolk shrinks from the vitelline membrane, and the space thus formed is filled with pervitelline liquid. In this condition one side—the future ventral plate—is flat, the other convex. The contraction of the yolk causes the blastema to be moulded on the underlying yolk-corpuscles, so as to mark out the surface of the egg into polygonal areas. The central nucleus divides up, and the nuclei thus formed, together with corresponding portions of protoplasm, migrate to the surface and enter the blastema; and thus this layer becomes converted into a series of nucleated cells—the blastoderm. The second period includes the changes up to the first appearance of the appendages. The irregular cells of the blastoderm divide up and give rise to regular cells. In one instance the author observed a depression at one pole of the egg, similar to that described by Salensky as an invagination; but Locy is uncertain as to what really happens, and considers it to have some relation to the primitive cumulus. This latter structure is a thickening of the blastoderm at one end of the ventral surface. At the opposite end a caudal thicken- ing appears, and between the two is the ventral plate. This is soon marked by transverse furrows into “ protozonites.” These extend laterally for about a quarter of the circumference of the egg, whilst the series of seven or eight zonites occupy about two-thirds the circumference. The blastoderm along the ventral surface is more than one cell layer thick, whereas dorsally there is a single layer of flattened cells. When the protozonites are formed, both ectoderm and mesoderm are distinguishable ; the former as a layer of regular, columnar cells ; the latter of cuboidal cells not so definitely arranged. The third period extends from the appearance of the appendages to the time of reversion. Six protozonites are distinguishable ; these soon become rounded at their lateral extremities and project as bud-like processes—the appendages. The first two zonites are formed from the cephalic plate; new ones are added from the caudal plate. The four next zonites appear, and have small rounded prominences upon them—the provisional mesosomatic appendages. The prosomatic appendages ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 601 gradually curve towards the ventral surface and are distinctly four- jointed. The cephalic plate is bilobed; a bilobed labrum has appeared and the stomodeum is faintly indicated between the rudiments of the chelicere. The head and tail nearly meet dorsally and the caudal plate has given rise to six metasomatic segments. The ectoderm along the ventral mid-line is thinner than at the sides, and it is from the thickened lateral bands that the nerve-ganglia are formed, one at the base of each of the appendages; those belonging to the chelicere will soon disappear. The mesoderm is absent in the middle line, but laterally it splits into somatic and splanchnic layers, and is d vided up into segments. In the fourth period the reversion takes place. The tail gradually becomes pointed and much shorter; the terga, which have appeared in the mesosomatic segments grow dorsally, and the tail gradually separates from the head on this surface. As the terga grow this process goes on till at the end of this Stage the ventral surface is bent upon itself, so that the tail is directed towards the head in exactly the opposite direction to what it is at the beginning of the period. The stomodzum is deepening ; the procto- deum has appeared at the tip of the shortened tail, and gives off a diverticulum which becomes the stercoral pocket of the adult. During reversion the ectodermic bands, which give rise to the ganglia, become widely separated and allow some of the yolk to project, so as to form a sort of yolk-sac, which, however, is soon absorbed. At the base of the cheliceree certain cells become spongy and form the poison-gland, probably by invagination ; the spinning glands are indicated by masses of ectoderm near the anus. Later on the in- vaginations to form the pulmonary sacs appear; the lamella arise from cells which become arranged in parallel lines. The mesoderm grows dorsally and becomes segmented, corresponding to the terga; so that these are not derived, as Balfour held, from the yolk. The author was unable to ascertain the details of the formation of the heart, but agrees with Schimkewitsch that Balfour’s statement that it arises from a solid cord of cells is wrong. Just before reversion commences certain large cells are seen along the sides of the body, which have arisen from the yolk, and form the “ primary entoderm,” The fifth period lasts up till the embryo is hatched. A deep con- striction separates the prosoma from the mesosome, and the embryo becomes still more flexed. The two posterior pairs of provisional appendages are transformed into spinning mamille. A few days before hatching the embryo begins to unroll and undergoes a moult, and when hatched is quite straight. The eyes have appeared, and the trachez are indicated as invaginations on the ventrai surface. 3. Organogeny.—At the time of hatching, the alimentary tract consists of an anterior and a posterior portion, the inner ends of which abut on the yolk. The stomodeum gives rise to pharynx, cesophagus, and stomach, which are lined by a cuticle continuous with that of the exterior. The proctodeum gives rise to the stercoral pocket, 602 SUMMARY OF CURRENT RESEARCHES RELATING TO from which the prestercoral tube leads towards the yolk; the Mal- pighian tubes arise from its dorsal wall, and the author considers that their position marks the prestercoral tube as entodermic. Pass- ing backwards from the stomach is the postgastric tube, which is so plugged with cells that its true relations are obscured ; it is probably the most anterior region of the mesenteron, the middle region of which is still occupied by yolk. The eyes are eight in number; the anterior median pair have a slightly different development from that of the remaining eyes. A thickening of the ectoderm appears, and at one end of this is an invagination, directed obliquely to the surface, so that the outer wall becomes inverted, whilst the cells of the lower wall retain their original direction; this consists of one layer, the inverted wall of several layers. The epidermis meets above the invagination and gives rise to the vitreous body ; the cuticle becomes thickened to form the lens; the cells of the inverted layer elongate and form the bacilli peri- pherally, whilst the nuclei get pushed deeper down, so as to be post- bacillar ; the lower wall of the optic cup appears to give four pigment- cells. In the other eyes, the nuclei of the retina are prebacillar. The lung-sacs arise as a pair of invaginations, and the lamelle are first indicated by the nuclei of the cells being arranged in parallel rows; the cells give rise to a chitinous cuticle which coats the lamella. At the end of the paper some results and theories of previous authors are discussed in the light of the new facts observed by the present author, and a bibliography closes the memoir. e. Crustacea. Structure and Development of Branchipus and Artemia.*— What Prof. C. Claus did long ago for the Schizopoda in his monograph on Nebalia, he has now even more completely achieved for the Phyllopods in a detailed investigation of the structure and develop- ment of Branchipus, nor is his research without rich results in regard to the Malacostraca in general. I. The formation of metameres and the development of the body during metamorphosis. —'The newly liberated Branchipus larva, though predominantly nauplioid, already exhibits hints of the meta- nauplius stage, in the presence, below the cuticle, of the maxillary segments, of pad-like appendages on the next two joints, and of meta- meric segmenting of the mesoderm band in the posterior portion. On cross-section the cerebral and mandibular ganglia are seen still connected with the ectoderm, the cesophageal ring and antennary ganglia have already sunk inwards, while antennary gland, liver diverticula, mouth, and hind-gut are readily apparent. The splanchnic * Arbeit. Zool. Inst. Univ. Wien, vi. (1886) pp. 267-370 (12 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 603 mesoblast develops, in characteristic crustacean fashion, independently of the somites, into which the parietal sheath becomes subsequently segmented. The growth of the mesoblast, the appearance of the lateral appendage-rudiments and alternating ganglia, the mesoblast growth round the dorsal vessel, and the progressive differentiation of the organs is then described in detail for larvee at various successive stages. The presence of a hitherto overlooked sense-organ between the brain and the frontal eye is noted. II. The segmentation of the mesoderm and the differentiation of ectodermic and mesodermic organs.—The posterior portion of the mesoderm band, Prof. Claus calls the budding zone. In front of this, cross bands of two cells abreast are formed, rapidly growing, by the division of these cells, into thick mesoderm somites, in which three regions become more or less clearly distinguishable—the dorsal, forming the heart-rudiment and dorsal muscles—the median or lateral forming the musculature of the joints—the ventral forming muscle and neurilemma. The connective tissue of the horizontal septum, _the blood-corpuscles, &c., are similarly derived. The first rudiments of the appendages are due to ectoderm proliferations which soon become associated with mesoderm. It is worth noting that except in the testicular cells no nuclear spindles were seen, so that direct division is regarded as normal. ‘The rudiments of the ganglia are at first: separate ectodermal thickenings, which, sinking in, become secondarily connected. In no case does a nerve arise as a secondary outgrowth from the nerve centre; only the frontal sense-organ seems to develope in this way from processes of the frontal nerve-cells of the cerebral ganglion. The grouping of the muscle-cells in definite direction is then described. Il. The formation of regions and the number of the segments.—The impossibility of establishing exact homologies between the variable adaptive modifications into head, thorax, and abdomen in different types_is emphasized. Entering into a detailed discussion of the number of segments, Prof. Claus criticizes the famous experiment of Schmankewitsch, maintaining that there is really no difference in the number of abdominal segments, while there are indeed numerous distinctions between the two genera. IV. Integument, connective-tissue, and fat-bodies.— Branchipus affords beautiful illustration of the chitinous modification of part of the protoplasm of the hypodermis cells to form not only the cuticle, but the sinews and internal plates. The three layers described in Decapods are not differentiated in Branchipus, where the external structureless cuticle is generally alone discoverable, though in some regions a deeper fibrous layer can be detected. It seems sometimes as if the connective-tissue structures which Tullberg described, in the lobster, between the chitinogenous cells and the subjacent connective tissue, were really present, but this appearance is due to a non-nucleated internal cuticle, resulting from the modified basal protoplasm of the epithelial cells. Connective fibres abundantly distributed in the joints are also products of the chitinogenous cells 604 SUMMARY OF CURRENT RESEARCHES RELATING TO of the hypodermis, and are not strictly connective-tissue fibres. The fibrous strands and sinew-plates produced within the chitinogenous cells are micro-chemically distinguishable from the superficial chitin of the cuticle. The mesoderm connective-tissue elements are then discussed, and the special modification of these by the accumulation of fatty globules within the protoplasm. The various distribution of the fatty cells and the parts that they seem to discharge, for instance, in aiding the chitinized basal membrane of the hypodermis cells to form the sinew-plates are described at length. V. Musculature.—Two dorsal muscles extend along the blood- vessel, and two ventral along the nerve-cord; the external bundles of the latter diverge dorsally in the segments behind the genital region; the myomere of the last abdominal segment is well defined from the anal piece (not in Artemia), but several long muscle-cells pass into the latter. The lateral-dorsal, and the median-ventral groups of transverse muscles, and the disposition of the component bundles in each appendage-bearing segment are described, and compared with the homologous musculature of the maxille, and with the more complicated modifications in the second antennary and mandibular segments. Special attention is directed to the interesting connection between the muscles themselves and with the integument, by means of numerous sinewy connective fibres which distribute the strain over a large surface of insertion. VI. Nervous system and sense-organs.—Branchipus, like other Phyllopoda, affords beautiful illustration of the rope-ladder-like nerve chain, produced by the marked distance of the two ganglionated cord and the consequent breadth of the transverse commissure. The position of the antennary ganglia on the cesophageal ring and the persistent separation of the mandibular and maxillary ganglia, are also regarded as expressions of primitive characters. With the exception of that connecting the mandibular ganglia, the commissures of the above ganglia are double, as are also those of the two pairs of small ganglia in the genital segments. Prof. Claus gives reasons for regarding the primary cerebral ganglion mass as referable to the apical dise of Lovén’s larva, while the ganglia of the segments owe their origin to paired thickenings of the hypodermis. He gives a minute description of the structure and histology of these supra- cesophageal nervous structures, of the sensory sets on the antenna, &c.,and of a hitherto unobserved sense-organ, similar to that structure in Cladocera first described by Leydig as “ Nackenorgan.” VII. The stalked eyes.—Prof. Claus emphasizes what even Carriére in his recent work on the comparative anatomy of optic organs overlooks, that the compound lateral eyes of Branchipus are seated on movable stalks, and indicates the great interest of their relatively simple relations as elucidating the more complex structures and connections in the eyes of Decapods and Stomatopods. After noting the perfect homology of the eyes of Branchipus with those of these higher types, and reasserting his previously maintained derivation of these organs from parts of the head which have become ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 605 independent, and not from modified appendages as was formerly asserted, he indicates the origin of their ganglion from the distally constricted portion of the dorsal cerebral lobe (the secondary cere- brum). A detailed comparative account of the innervation and his- tology of these lateral eyes is then given, with critical notices of the opinions of Grenacher, Carriére, and others. VILI. The unpaired frontal eye is then described; and in regard to its function, it is noted that while the absence of a refracting apparatus seems to exclude the possibility of the perception of images, and points, therefore, to a diffuse sensitiveness to light, the slight differentiation of the nerve-cells suggests the probability that its function is restricted to a susceptibility to the heat-rays of light. TX. Alimentary and excretory organs.—After some notes in regard to the oral appendages, in the course of which the absence of a mandi- bular palp is emphasized as a general character of the Phyllopods, and a description of the alimentary tract, with a denial of the respira- - tory function of the hind-gut, Prof. Claus discusses at some length the antennary and the shell-glands, as also the interesting segmental, ventral, and limb “ glands,” and lastly the “ Nackenschild.” X. Heart, circulation and respiration —In regard to the structure and development of the primitive type of heart exhibited by Bran- chipus, Professor Claus has little to add to his previously established results. The same may be said as to the respiration ; as before, he maintains, apart from the respiratory function of the whole of the delicate integument, that the branchial sacks on the appendages are special breathing organs. As noted above, he does not allow to the intestinal surface that respiratory function with which it has been repeatedly credited. XI. Reproductive pea EG modification of genital segments and external organs, and the structure of the male and female glands, are finally discussed, and on the former point a further report is promised. Of this detailed monograph of the much-investigated Branchipus, which occupies a whole part of the Wien Arbeiten, little more than a table of contents has been above given. The memoir is illustrated with twelve plates. ‘Challenger’ Stomatopoda.*—Mr. W. K. Brooks gives a résumé of his report on this group published in the “ Challenger ” Reports. Out of fifteen adult species eight are new, and two have been only inadequately described. The pelagic larve are numerous, and haye served to establish the connection between the adults and their proper larva: in all the genera except two. The development, however, is difficult to trace; they undergo secondary modifications which are not represented in the adult; in fact, the larve differ more from one another than do the adults. From a comparative study of the larve, it is possible, as with the * Johns-Hopkins Univ. Cire., v. (1886) pp. 83-5. 606 SUMMARY OF CURRENT RESEARCHES RELATING TO adults, to arrange them genealogically, as the following tabular arrangement shows :— Alima Lysioerichthus (with short spines) Alimerichthus Lysiocrichthus (with long spines) \ é Erichthalima Pseuderichthus Gonerichthus Unknown Erichthoidina-like larva, The generic characters are then given: while retaining the accepted genera new diagnoses are rendered necessary, since im- portant points have been too greatly emphasized. Then follows an analytical key, giving the more prominent diagnostic characters of each genus. 1. Sixth abdominal somite fused with telson (gen. Proto- squilla n.g.). 2. This somite distinct. Genera, Gonodactylus. Pseudosquilla. Coronida n.g. Lysiosquilla. Squilla. A phylogenetic table of the adult takes the following form :— Squilla Lysiosquilla Squilla (Chloridella) Ly. (Coronis) Coronida Pseudosquilla Gonodactylus | | | Protosquilla This table agrees with that derived from consideration of the larve. Faxon has reared a Squilla empusa from Alima ; Claus has traced Pseudosquilla from Pseuderichthus ; and Brooks has now traced ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 607 Lysiosquilla excavatus from a long-spined Lysioerichthus, L. maculata from a similar larva with short spines, Gonodactylus from Gonerich- thus ; and probably Erichthalima is a young Coronida. New Isopod.*—Dr. R. Koehler proposes the name of Jeropsis brevicornis for a new Isopod which he found in the island of Sark, where it lives among sponges and simple Ascidians. As its name im- plies it stands nearest to Jwra, from which it differs essentially by the characters of its antenne. It is from 2 to 2°75 mm. long; the seven thoracic somites are separated from one another, at the sides, by spaces of some size; the integuments are colourless, save near the head, where there is a large brown spot. The head is large and quadri- lateral; the lower antennz have a peduncle composed of four joints, the first of which is very short; the second is longer, but wider than long, and swollen along its outer edge; the third is almost triangular, and is, as it were, placed in an angle between the second and fourth joints; the fourth joint is oval; the flagellum of this antenna is very short, and is made up of seven or eight rings which decrease rapidly in size from the proximal to the distal. The superior antennz have a peduncle of five joints and no flagellum. In a number of characters the new genus resembles Jera, but in addition to those already mentioned, it differs also in the form of the maxillipeds, and in the appendages of the sixth abdominal segment. Entoniscus moenadis.t—M. A. Giard found an Entoniscus on the left side of a Carcinus meenas, in the midst of the hepatic ceca of its host. It differs from F. cavolinii, not only in colour but also by the characters of its embryo; this has no nauplius-eye, and there are differences in the iateral eyes. M. Giard accepts the theory of pro- tandrous hermaphroditism with regard to Hemioniscus, Entoniscus, and other less abnormal Bopyride. MM. A. Giard and J. Bonnier also report} that the cuticle of Entoniscus is covered with small chitinous hairs, which are, no doubt, destined to aid the movements of the parasite in its host; in the caudal region the enveloping membrane which belongs to the crab is strengthened by a chitinous secretion, in which there is an orifice by means of which the parasite is put into communication with the branchial cavity of the crab. The incubation-cavity is more com- plicated than Kossmann supposes. The authors’ studies on develop- ment have been few, but they are able to say that invagination is epibolic. EH. Kossmanni found on Portumnus variegatus, and E, fraissi on P. holsatus, are new species. Australian Fresh-water Entomostraca.$—Prof. G. 8. Brady gives a list of the species of fresh-water Entomostraca that have already been described from Australia, and an account of fifteen species, eleven of which are new; these last belong to the genera Limnetis, Eulimnadia, Estheria, Cypris, Chlamydotheca, Cydridopsis, Notodromos, and Candona. * Ann. Sci. Nat. Zool., xix. (1885) Art. 1, 7 pp. (1 pl.). + Comptes Rendus, cii. (1886) pp. 1034-6. t Tom. cit., pp. 1173-6. § Proc. Zool. Soc., 1886, pp. 82-93 (3 pls.). 608 SUMMARY OF CURRENT RESEARCHES RELATING TO Orientation of Sacculina carcini.*—M. A. Giard deals with some criticisms of M. Yves Delage. M. Giard has urged that Sacculina carcini can only be explained on the theory of modified descent, by supposing that the parasite of the symmetrical crab is derived from a Peltogaster parasitic on an anomurous form with twisted tail, which was the ancestor of the Paguride. In answer to M. Delage’s objection that it isimpossible to accept the theory of the derivation of the Brachyura from the Paguride, it is answered that all that is necessary is to show that the Paguridw have given rise to certain crabs with a symmetrical abdomen; this has been demonstrated by Boas, who has shown that Lithodes is really descended from Eupagurus, and Birgus from Cenobita and the Paguride. Against the explanation offered by Delage that the movement of rotation which sets the axis of the Sacculina perpendicular to that of the crab is due to the right receiving more nourishment than the left side, it is sufficient to cite the case of Sacculina benedeni, which attaches itself to Grapsus; in this crab the unpaired cecum opens from below the point where the Sacculina is ordinarily found, and yet the parasite presents just the same characters as in Carcinus mznas. As to the term to be applied to these parasites, no organ of the Sacculina, except the roots, can be properly said to be internal; the epithet is good for a certain time, from the topographical point of view, but it is not exact as a morphological application. The method of teasing out the intestine of the crab is too coarse, and has led M. Delage into error. M. Y. Delage resents t M. Giard’s criticism, but no new facts are contributed. Vermes. Generative Organs of Earthworms.{—In all the species of Lum- bricus examined by Dr. R. 8. Bergh the gonads were found to be in the segments described by Hering. They agree in structure, but the testes vary in form in various species more than the ovary does. The gonads appear during the last period within the cocoon, and have at first the same appearance and structure. Arising as club-shaped thickenings of the peritoneum, they very early become differentiated into a thin epithelial cortex (peritoneum) and an internal mass of primitive germinal cells with peculiar large nuclei. With regard to the anatomical relation of the seminal vesicles the species of Lumbricus fall into two groups, which appear to harmonize well with the divisions which have been instituted by systematists. In L. terrestris there is a median unpaired vesicle in the uinth and tenth segments, which invests the testes, seminal infundibula, and ventral chain. With this there are connected three pairs of appendages, which lie in the eighth, tenth, and eleventh segments, A similar arrangement is found in L. purpureus, and, according to Hering, in L. rubellus. In other species (L. fetidus, L. riparius, L. turgidus, L. mucosus), there is no indication of an unpaired median vesicle, but * Comptes Rendus, cii. (1886) pp. 1082-5. + Ibid, pp. 1336-8, { Zool. Anzcig., ix. (1886) pp. 231-5. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 609 there are four pairs of vesicule seminales in the cighth to eleventh segments, The origin of the paired vesicles has been investigated in L. tur- gidus. They do not, as Lankester supposed, arise as outgrowths from the seminal funnels, but are developed quite independently of these. They are formed as folds of the dissepiments, and the two anterior project forwards, and the two posterior backwards. The appendages of the median vesicle of L. terrestris arise in just the same way, but it is not yet made out how this vesicle itself is formed. The receptaculum ovorum collects the ova until a sufficient num- ber have been given off from the ovary to be laid. This was correctly explained by Hering in L. turgidus. It has primitively no connection with the oviduct or the funnels, but arises in just the same way as the paired vesicule seminales, with which it is completely homologous. Later on, however, it becomes connected with the oviducal funnel. The receptacula seminis present variations in number and position, and never appear till very late. They are primitively invaginations of the epidermis of the intersegmental groove, but this invagination merely gives rise to the epithelium of the receptacle. The peritoneum forms their outer muscular layer, and they cannot be regarded as seg- mental organs, as Lankester and others suppose. In a postscript the author gives an account of his examination of two species of Pericheta. The testes and ovaries are in exactly the same segments as in Lumbricus, but the former have undergone a peculiar dislocation, for they are not now placed directly on the hinder aspect of the special septa, but are removed from them, and, with the seminal infundibula, lie enclosed in a capsule of connective tissue. The testes have just the same structure as those of L. tur- gidus. ‘There are two pairs of vesicule seminales (these have been previously described as testes), which open into the capsule. The ovaries are remarkable for consisting of a number of cylindrical ovarian cords radiating from a common base ; as this allows of a number of ova being given off at once there are no receptacula ovorum. The oviducts open to the exterior by a common orifice on the thirteenth segment. In one {* Horst’s”’) species there are four pairs, and in the other two pairs of seminal pouches. Ovum of Clepsine and Gnathobdellide.*—Dr. R.S. Bergh finds that the ova of Clepsine are well adapted for embryological investigations, owing to their large size and the ease with which they can be pre- pared. He finds that the trunk-germs, and therefore the whole of the trunk of the leech (with the exception of the midgut), arise from the fourth larger cleavage sphere, while the cephalic germs are to be referred to the smaller blastomeres. Each of these primary rudiments is afterwards differentiated into ectoderm and mesoderm. The author makes some criticisms on the results of Whitman and Nusbaum. Leeches of Japan.t—Dr. C. O. Whitman in his first paper on the leeches of Japan, treats of the Hirudinide or ten-eyed leeches. In * Zool. Anzeig., ix. (1886) pp. 112-9. 7 Quart. Journ. Micr. Sci., xxvi. (1886) pp. 317-416 (5 pls.). Ser. 2.—Vo.. VI- Qs 610 SUMMARY OF CURRENT RESEARCHES RELATING TO it considerable attention is given toa comparative study of the different genera, with the object of finding a more satisfactory basis for classification than any yet employed. AI] the Hirudinide agree in having twenty-six somites between the first pair of eyes and the aceta- bulum. There is a general law of abbreviation which is true of both ends of the leech, and the extent of this, which consists in the suppression of from one to four of the less important rings in the extreme somites, not only furnishes excellent means for distinguishing genera and species, but also gives a key to their phylogenetic relationship. The land-leech (Hemadipsa) is first considered. H. japonica is a new species. The author points out that the land-leech, in abandoning the aquatic mode of life, became more and more adapted for creeping till at last the power of swimming was completely lost. This change in habit was accompanied by adaptive changes in size, form, and proportions ; the centre of gravity travelled backwards nearer to the posterior sucker, while muscular power became more and more concentrated. The nephridial vesicles are capacious sacs, and experiment shows that fluid can be discharged from the nephridia for the purpose of moistening the surface of the body. The skin-glands are more numerous and the nephridial vesicles more capacious in terrestrial than in aquatic leeches. Further, the nephridial pores are marginal, and not latero- ventral in position, as are those of Hirudo. In all land-leeches which have been examined by Dr. Whitman, there have been noted the absence of an eyeless ring between the two rings which bear the third and fourth pairs of eyes; the marginal position of the nephridial pores; the large size of the vesicies; and the peculiar lobes which cover the posterior pair of pores. All these characters appear to be due to the change of respiratory medium, but the land-leeches still require to live in air which is loaded with water; they are animals “still on the road to terrestrial life.” Hirudo nipponia sp. n. is next described, and the discussion of its characters leads the author to givea revised definition of the genus Hirudo, With it he compares Aulostoma and Heemopis, the latter of which he proposes to replace in Hirudo, the comparative number of denticles being of no importance in the defini- tion of a generic group of the Hirudinide. By a comparison of Hirudo medicinalis, Aulostoma, Hirudinaria javanica and Leptosoma (g. n.), the author illustrates the value of the somites as a basis for classification. This last-named form has fewer abbreviated somites than the other forms described, and so shows that it is more primitive than any known Hirudinid. The fact that the denticles are rudimentary or absent suggests affinity to Aulostoma, but the latter is clearly an offshoot of Hirudo, so the edentulous condition must be supposed to have been acquired independently. L. pigrum, L. edentulum, and L. acranulatum are the new species of this new genus. ‘The generic and specific characters of Macrobdella sestertia are fully given. In conclusion Dr. Whitman speaks of the segmental papille, which, as he has already taught us, are serially homologous with the eyes. They are sense-organs, and from them the eyes are developed, so that they may be regarded as incipient eye-spots. These segmental > ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 611 organs do not appear to have given rise to the non-segmental organs which are limited to a specialized part, and have arisen in response to the increased needs of their possessor. In the land-leech it is possible that, in addition to distinguishing between light and darkness, the segmental organs have some olfactory function, but this does not appear to hold good for Macrobdella. Metamorphosis of Aulostoma gulo.*—Dr. R. 8. Bergh describes the larva of Aulostoma gulo as varying in size, and having an oval form of body in which the body-wall and enteric wall are widely separated from one another; the cesophagus lies on the ventral surface, and may be single or divisible into pharynx and cesophagus proper; behind the mantle are the stripe-like fused trunk-rudiments, and at the sides of these the four pairs of circular primitive kidneys ; all the structures of the larva fall into two distinct categories, those which have already specific functions, and those which are still indifferent cell-masses. To the former group there belong the primitive epidermis and the subjacent muscular and nervous cells of the body-wall, the enteric canal, and the primitive kidneys; to the latter the head and trunk-germs. The primitive ectoderm is a simple flattened epithelium, the boundaries of the constituent cells of which are not apparent; the musculature consists of two different kinds of smooth elements ; some are small and closely packed, the others are large and do not form a true muscular layer, their cells being separated from one another by rather broad intermediate spaces; they are, as a rule, arranged transversely, and so appear to form the circular muscle of the body. The excellent description given by Leuckart of the muscular system of the larva of the medicinal leech agrees essentially with that of Aulostoma. Cells which are apparently nervous in nature are to be found scattered between the muscle-fibres; they are spindle- shaped or much branched, and their processes are often exceedingly long and fine. The enteric canal is divisible into an anterior cesophageal portion and a midgut, which ends blindly; the former has a surprisingly complicated structure, for it consists of four distinct layers: an epithelial without distinct cell-boundaries, a layer of circular and then a layer of radial muscular cells, and an outer layer of epithelium. The midgut has the form of a simple sack which occupies by far the greater part of the cavity of the body ; its walls are simple in structure. The four pairs of primitive kidneys, which are ventral in position, are circular closed organs, formed of two rows of cells; in the anterior pairs a canalicular structure can be easily made out, and here and there there are anastomosing tubular spaces; the cell- boundaries, however, are indistinct, and the cells elongated. The head-germs lie in front of the esophagus, between it and the epidermis, and have, at an early stage, a broad tri- or quadri- lobate form ; they early unite with one another, as do also (in contra- distinction to Nephelis) the trunk-germs ; these latter are much better * Arbeit. Zool.-Zoot, Inst. Wiirzburg, vii. (1886) pp. 231-91 (4 pls.). 28 612 SUMMARY OF CURRENT RESEARCHES RELATING TO developed than the head-germs; they extend as far as the hinder end of the pharynx, and are not connected with those of the head ; posteriorly they terminate a little short of the hinder end of the larval body. They are at first separate, but later on they fuse, at first in their hinder and then in their anterior portion. From their outer margin the primitive kidneys are budded off, as simple rows of cells, each of which forms a swelling at the lateral margin, and still later separates from the germ. The history of the kidneys is given in detail. The author prefaces his account of the formation of the body of the adult by a statement of the views held by earlier writers; he himself finds that the primitive cesophagus, like the primitive ectoderm, is a provisional transitory structure, no signs of which are to be found in the adult; instead thereof there is formed by the union of the head and trunk-germs, and the invagination which takes place at the point where the primitive mouth was situated, the permanent cesophagus of the leech. In the Gnathobdellida the hind- ent is not formed by the invagination of the primitive epidermis, but as a growth from the trunk-germs. Of the larval body nothing remains but the endoderm, and the body of the leech is formed by the hind and trunk-germs, which grow around the epithelium of the midgut. After a critical review of what has been effected by his pro- decessors, the author considers the question of the typical develop- ment of the Annulata; the first important point is that the body is wholly or partially built up of two pairs of germs, an anterior and a posterior, which are, histologically, exactly similar, and which grow around the mouth and enteron. In the clearest cases (Ne- mertines, Leeches) there are four primitively common collective structures which contain the rudiments of all the tissues and organs, and from which the definite layers and tissues are only secondarily differentiated. This “scheme” is essentially that of those whose ova are provided with a small quantity of nutrient yolk, and they must be regarded as the typical, since all can be easily referred to them. Though this might seem to show that the Nemertinea and Hirudinea are closely allied, the author regards the latter as true Annelids; he finds an explanation in the fact that the Nemertinea have the simplest, and the Hirudinea the most specialized mode of development. In the Nemertinea all the tissues of the body (with the exception of a part of the enteric epithelium, and, perhaps, the lateral organs) are typically formed from five germs, which (in Pilidiwm) arise as hollow invaginations of the primitive ectoderm and grow around the mouth. There is a late differentiation of the various parts in the larve. In the Polycheta and Oligocheta the four germs are from the first differentiated into two parts, so that there are, so to speak, eight germs; these do not arise as hollow invaginations, but as solid growths of the ectoderm, and the distinction between the provisional and the permanent epidermis is no longer possible; there is a partial early differentiation. In the Leeches this early differen- ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 613 tiation is not partial, but complete; at least for the trunk-germs ; Bergh has shown that the ten cells which appear during cleavage give rise to them. Here again there is a distinction between pro- visional and permanent epidermis, and the similarity to the Nemer- tinea is due to the secondary union of the permanent ecto- and mesoderm. The investigations which the author has been able to make into the history of the development of the earthworm have shown him the accuracy of many of Kleinenberg’s statements, and have convinced him that the trunk-germs of leeches are not, as is ordinarily supposed, exactly homologous with the mesodermal stripes of Lumbricus, but that the latter structures correspond to a part of what are contained in the former. Structure of the Glandular Ventricle of Syllis.*—Mr. W. A. Haswell prefers the term gizzard for that part of the digestive tract of the Syllide which has been called glandular ventricle, for he finds that there are no glands in the walls of this organ, but rather - muscles; these have been supposed to be glands (possibly) because they form hollow columns of striated muscle; the transverse striz are better marked in some than in other species. As to the con- stituent elements, it is found that they retain an embryonic structure inasmuch as there is a polynucleated core; this is of a red colour in a fresh state, like nearly all the protoplasmic elements of the body of the annelid. In one species the fibrils were seen to be formed by the linear coalescence of rows of the large rounded granules of which the main substance of the core is composed. Mr. Haswell reminds us that hollow polynucleated fibres of striated muscle-substance are found in various vertebrates, as an embryonic condition of the solid fibres, and in certain insects and arachnids as a permanent form. Simple (mononucleated) hollow fibres are not unfrequently found in various Vermes, and are in some cases transversely striated. Ovaries and Oviducts of Eudrilus.t—Mr. F. E. Beddard directs attention to the fact that in a species of Hudrilus the oviduct is per- fectly continuous with the ovary; this is novel to the whole group of Cheetopoda, and resembles the arrangement seen in Platyhelminths and Hirudinea, New Ichthyobdellid.{—M. R. Saint-Loup describes a new form of ichthyobdellid—Scorpenobdella elegans, which was found parasitic on Scorpena scrofa. It is 85 mm. long and 2 mm. wide behind the oral sucker, and is of a brownish colour with black dots and larger white patches. The walls of the body exhibit the typical hirudinid arrangement, the digestive tube is remarkable for the absence of any metameric divisions; there are no lateral ramifications and no con strictions; there is a proboscis connected by two muscular bundles with the walls of the body; the posterior portion (cloaca) is remark- * Quart. Journ. Micr. Sci., xxvi. (1886) pp. 471-9 (1 pl.), + Zool. Anzeig., ix. (1886) pp. 342-4. ¢~ Comptes Rendus, cii. (1886) pp. 1180-3. 614 SUMMARY OF CURRENT RESEARCHES RELATING TO able for communicating with two lateral canals; these canals pass forwards for about 6 or 7 mm.; this is an arrangement which has not been described in any other leech. The cervical part of the nervous system is reduced to a com- missure ; and the epidermis is segmented in metameres corresponding to those of the nervous system. There are five pairs of testicles, and two saccular ovaries. Glands comparable in form and position to what are ordinarily called salivary glands are to be found in the anterior region of the body, between its walls and the proboscis. ‘Challenger’ Polycheta.*—An elaborate report on the Polychaeta collected during the voyage of H M.S. ‘Challenger’ has been pub- lished by Prof. W. C. M‘Intosh; the series is described as being extensive; no representatives of new families were found, but there are 220 new species. In addition to the technical descriptions of the forms, whether old or new, there are accounts of the eyes of the Alciopide and Phyllodocide by Dr. R. Marcus Gunn. The report is indispensable to all workers on Annelids. Embryology of the Nemertinea.t—Prof. A. A. W. Hubrecht here gives the English reader an account of his observations on the develop- ment of Lincus obscurus, which were published last year in Dutch. Four discs, and subsequently a fifth, are formed by the epiblast; the former are due to the cubical epiblast-cells dividing lengthways, becoming overcapped by the surrounding epiblast and soon completely enclosed within it. The fifth dise appears thus; in the aboral region of the epiblast the epiblast-cells are very distinctly delaminated, and a double layer is formed which finally separates; all the five discs are one cell-layer thick, and they increase in size by continued division of the constituent cells ; finally they meet along their edges; they then unite and form the continuous coat of secondary integument, outside of which the primary epiblast is very soon cast off. Only at first is the hypoblast a distinct unicellular layer; later on its walls become less distinct ; by budding mesoblast-cells are developed, which perform amceboid movements in the blastoccel into which they escape; some of them arise from the epiblast and some from the hypoblast, and there is no definite localization of this process. It was noted that the chromatic nuclear substance of the primary epiblast diminishes near the time when it is going to be cast off; this decrease in the significance of the primary epiblast as a formative element becomes more and more marked as the young larva within it increases in size. Prof. Hubrecht is of opinion that the primary epiblast is not dis- integrated, but that the greater part of it is carried off by the mesoblast eells or plays a further part in the formation of the larva. No portion of the central nervous system of Lineus takes its origin from either primary or secondary epiblast, but the whole nervous system is of mesoblastic origin. At first the archenteron communicates with the * Reports of the voyage of H.M.S. ‘ Challenger,’ xii. (1885), xi. and 554 pp. and 94 pls. : + Quart. Journ. Micr. Sci., xxvi. (1886) pp. 417-48 (1 pl.). } 4to, Utrecht, 1885. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 615 enteron by a wide blastopore, but later on the cavity of that portion of the intestine which grows backwards is closed anteriorly, and in front cf this another portion of the embryonic intestine constantly remains in open communication with the exterior; the anterior fore- gut opens by a crescentic slit, and this would seem to become the mouth of the adult; in other words, there is no epiblastic stomodceum ; part of the fore-gut becomes the cesophagus, and the rest appears to be converted into the nephridial system. The nephridia seem to long remain in a more or less embryonic phase, but their history is very difficult to make out, and is as yet only incompletely known. The mesoblast cells, once freely moving about in the blastoccel, soon accumulate against the inner surface of the plates of secondary epiblast, and the mass increases in size. The process of differentia- tion leads to the appearance of muscle- and nerve-cells at a very early date; the mesoblast cells form a massive group in the prostomium, and a comparatively thin cell-sheet in the rest of the body. Unexpected as is the mesoblastic origin of the nervous system, there appears to be no doubt about it; Hubrecht, indeed, thinks that Salensky’s figures of Amphiporus viviparus point to the mesoblastic origin of the nervous system in that animal rather than to the mode of origin approved by Salensky. An account is given of the other organs which are developed from the middle germinal layer, and, in conclusion, there are some observations on the differences between an archiccelic and a schizoccelic cavity; as to the latter term great care must be used in its application, and the extension made by the Hertwigs is unfortunate. An archicel is the term to be used when, as with Lineus, it is obvious that the cavity has been present from the begin- ning, while that of schizoccel may be reserved for those cases where it can be demonstrated that the perivisceral cavity originates by a process of active scission, and when this scission cannot be looked on as a derivate either of archi- or entero-ccel. Filaria terminalis.*—Count N. Passerini describes the anatomy and development of a Nematode found very abundantly in the lungs of rabbits, and named by him Filaria terminalis. Atter discussing the pathological state of the host, he gives a diagnosis of the parasite in the following terms :—the body is cylindrical, filiform, elongated, and transversely striated; the sexes are separate ; the head has an obtuse form, and is not distinctly separated from the rest of the body ; the terminal, circular mouth is surrounded by six papille; the anus lies ventrally and posteriorly, in front of a short, membranous, subconical tail; the extremity of the male is a little curved forward, and is furnished with a chitinous retractile penis formed of four pieces, of which the two terminal are slighily recurved anteriorly; the sexual aperture of the male lies at the hind end im a sort of cloaca (in which the intestine also ends), and is surrounded by six soft cirri, of which the first two are bifid at the apex, the two next divided into three, and the last simple; there is a single testicle; the oviparous female * Atti Soc. Ital. Sci, Nat., xxvii. (1884) pp. 42-63 (5 pla.). 616 SUMMARY OF CURRENT RESEARCHES RELATING TO is larger; the two ovarics lead into a vagina opening posteriorly, a little in front of the anus. Count Passerini describes (a) the structure of the ova, their division into morulew, the formation of the gastrula by delamination, the origin of the mesoderm from the proliferation of the endoderm, and the formation of the embryo within the egg-membrane. The larval form differs from the adult in its relatively greater breadth, in its sharply pointed tail, in the non-differentiation of the sex organs, in the relatively longer pharynx, and the absence of the six oral papille. The body is well protected by a chitinous coat, and like that of the adult, is striated, less distinctly anteriorly. The lateral canals and their external aperture at the end of the pharynx, are distinctly visible. The integument (b) consists (1) of a thin chitinous cuticle, con- tinued inwards to line the pharynx, and perhaps further ; and (2) of a delicate epidermis, in which the cellular structure could not be defined. Both exhibit during life fine transverse striations, due to a sort of permanent contraction of the subdermal muscles. (c) Below the epidermis lies a layer of longitudinal muscles which have a spindle shape, are drawn out at the ends, and exhibit distinct longitudinal striations, and one or more nuclei. Frequently there is on the inner face of the fibre a non-striated, protoplasmic portion, nucleated and slightly granular. The various special muscles, those protruding and retracting the penis, the ejaculatores of the testis, those associated with the abdominal cirri, &c., are then described. (d) The muscular, chitin-lined pharynx is suddenly constricted in front of the intestine, in such a way that the return of food is impossible. The delicate intestine, ending in a cloaca, into which the vasa deferentia also open, is lined by a simple epithelium of large polygonal cells. No glands were discovered. The contents consisted of pus globules with frag- ments of lung parenchyma and tuberculous sarcoma. (e) The lateral excretory” canals originate in a deep cecum in the tail region, and end similarly a little in front of the oral papillz. Where the pharynx joins the intestine the two canals are united by fine ducts, which unite and open externally. Further details as to contents, &c., are communicated. (/) Multipolar cells, occurring at both ends of the body, in connection with the papille, cirri, &c., are described as nervous elements. The male reproductive organs (g) are described at considerable length. There is but one large testis, the other having probably atrophied, A seminal duct connects the testis (which occupies a large part of the body) with the penis. The testicular cells are at first pyramidal, and exhibit a delicate apical “rachis,” this is after- wards lost, and the cells becoming free are modified into spherical spermatozoa. The penis, which serves to keep the vas deferens in connection with the vulva during copulation, consists of two elongated, toothed, chitinous bodies (corpi copulatori), each of which is muscu- larly connected with a terminal, recurved, toothed hook. The action of the various muscles is noted. The six soft anal cirri also aid in the copulatory act, embracing the posterior part of the body of the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 617 female, They are furnished with nerve-cells, and are probably also tactile. (h) The female reproductive organs are very well developed. The long ovaries, extending from the pharynx nearly to the hind end of the body, function posteriorly as oviducts, whence the eggs pass through a peculiar muscular collar into the vagina, which ‘s also furnished with delicate muscles. The young ova become fixed by a fine filament (rachis) to a sort of funiculus in the centre of the tube, they liberate themselves from’ the parietes, lose their rachis, and in the posterior portion of the ovary acquire their chitinous envelope. Notes on Entozoa.*—M. R. Blanchard reminds us that cysts of Teenia echinococcus are not rarely found in the horse, though they are not reported by Dr. Linstow as occurring in that animal. Amphistoma conicum, which is known to occur in cows of Europe and Australia, is now reported from Formosa. Ankylostoma bow is a new species from the intestine of a Boa constrictor; this is almost the first notice of a nematoid of this genus in an Ophidian, most of them living in warm-- blooded animals. Rictularia bouviert is a new species found in the intestine of Vespertilio murinus, but is described from a single (female) specimen; this is a very rare generic type, but there is in Dr. Dohrn a sixth observer, not noticed by M. Blanchard, nor is his species (R. macdonaldi), from a West. African bat, mentioned by the author in his synopsis or synonymy. Anatomy of Tenia lineata.t—Dr. O. Hamann gives a detailed account of this parasite of the dog; the ripe proglottis is remarkable for containing a rounded body, from which a much-coiled tube is given off; the body has a reddish colour, and, with the tube, is filled with embryos. After the joints have been deposited for two or three days the embryos are found in the spherical body only. The musculature is of a somewhat abnormal type, and may be arranged in two groups; in one we have the fibres in which the formative cells are retained, and in the other no remnants of these cells at all. In the first group we find the circular layer and the dorso-ventral muscles; on each fibre of the latter there is a large peripheral cell, which seen from the surface is oval or spindle-shaped in form; when seen from the side the connection between the cell and the fibre can be made out. In the second group are the fibres which le parallel to the long axis of the proglottis, the subcuticular longitudinal muscles, and the layer which surrounds the centrally placed organs. The characters of the longitudinal trunks of the water-vascular system vary considerably in different proglottids ; the trunks are lined by a fine hyaline membrane, secreted by flattened epithelial cells ; from the trunks there are given off fine canals, which can be followed for some distance; they. terminate in a funnel-shaped widened end; the course of the fine vessels is exceedingly irregular, they are much coiled and often branch; each lateral twig ends in a funnel; they are transparent tubules of 0°00142 mm. diameter ; * Bull. Soc. Zool. France, xi. (1886) pp. 294-304 (1 pl.). + Zeitschr. f. Wiss. Zool., xlii. (1885) pp. 718-44 (2 pls.), 618 SUMMARY OF CURRENT RESEARCHES RELATING TO below the funnel is a vesicular structure which partly projects into it. The funnels are often pretty close together. The generative organs are represented by a spherical body which lies at the hinder end of the proglottis, and gives off posteriorly a short tube, and anteriorly a longer one, which may be several times coiled; this last is the uterus; the spherical body is to be regarded as the shell-gland. The uterus is invested in a hyaline membrane formed by acell-layer; the epithelium ceases where the uterus passes into the shell-gland; between the ova there is a ground-substance, in which the eggs lie; in very thin sections this substance is seen to form a fine plexus, in which amceboid cells are imbedded; these appear to be unfertilized germ-cells. The vas deferens has its loops turned towards the dorsal surface. The vagina opens beneath the cirrus, and the orifices are (and this is important) on the flat surface of the body, not marginal. The author points out the differences between this species and the Teenia of man—they lie in the form of the oviform organ which he regards as representing the complex of gland-cells, which in other Teeniz form the shell-gland ; the position of the orifices, and the fact that the vaginal orifice lies above instead of below that of the cirrus ; the uterus recalls that of Bothriocephalus, as do too the forms of the eggs. The statements of Griesbach as to the tissues of Cestoda, of Salensky as to the musculature, and of Pintner as to the water-vascular system are examined and compared with the author’s results. In conclusion the author raises the questions, firstly, does the position of the generative orifices form a sufficient reason for establishing a new family for the reception of this species? and comes to the conclusion that it does not; secondly, does the fact that the uterus is coiled, instead of consisting of a median trunk with lateral branches, justify the formation of a new genus? the answer to this is in the affirmative, and the name of Ptychophysa is suggested. The forms, already described by previous writers as Teenia lineata, are, in the last place, examined. Genital Organs of Pontobdella muricata.*—M. G. Dutilleul reminds us that the male orifice of the hermaphrodite Pontobdella is large, and surrounded by a folded welt, and that the female orifice is small and not so surrounded. The male apparatus consists of testicles, deferent canal, seminal vesicle, efferent canal, and spermatophore- pouch. There are six pairs of white ovoid testicles, which decrease in size from before backwards; each is placed in a pouch formed by the dorso-ventral muscles, and consists of a poorly developed muscular investment, which is lined by the male epithelium; the canal from each testicle opens into a common duct which leads to the seminal vesicle. Below the sixth testicle it continues its course parallel to the seminal vesicle, then curves on itself at the level of the point of union of the vesicle with the efferent canal, forms a descending spiral, and opens at its base. This arrangement reminds us of what Quatre- * Bull. Sci. Dép. Nord, vii. and viii. (1884-5) pp. 349-54; ix, (1886) pp. 125-30 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 619 fages saw in Branchellion, and may be regarded as being the origin of the more complex arrangement which is seen in the higher Hirudinea. The seminal vesicle is large, and of a white colour; its efferent canal is more resistant in structure, and is so folded on itself as to take the form of a reversed U; the ascending is more muscular and less glandular than the descending branch, and has a much wider lumen ; the descending branch enters into relation with the efferent canal. The spermatophore pouch is ovoid in form, and soft; that of either side unites with its fellow by a short canal which opens at the male orifice ; itis essentially formed of long unicellular glands, surrounded by a common muscular investment; the short connecting canal is formed by the invagination of the integument at the level of the male orifice. ; The female apparatus consists of two ovaries, two oviducts, and two accessory glands; the ovaries are tubular, and often rolled round the vesicles, sometiines even round the nerve chain; their wall is delicate and transparent, and contains two planes of muscular fibres ; the oviducts are merely prolongations of the ovaries; the accessory glands give off two or three canaliculi which open into the canal which is formed by the fusion of the two oviducts; they are soft, and contain a reticulum of muscular and connective tissue in which uni- cellular glands are imbedded ; they are invested in a muscular sheath, by which they are, so far, distinguished from the Platyhelminthes. The general disposition of the genital apparatus recalls that of Branchellion and Batrachobdella, with which Pontobdella agrees in all essential points. Turbellaria of Lesina.*—In a preliminary communication Prof. L. vy. Graff gives an account of a few species. The accelous form which in 1874 he called Convoluta cinerea he now calls Cyrtomorpha cinerea ; it is very common at Lesina; the mouth is in front of and not behind the otoliths, the generative orifices are separate, and the penis is a conical protrusible papilla; the female orifice is fringed by powerful cilia; the otolith is imbedded in a protoplasmic process arising from the wall of its vesicle. Enterostoma Zooxanthella n. sp. is one of the smallest of the Turbellaria of Lesina; it is scarcely half a millimetre long; its dirty yellow colour is due partly to a brownish reticular pigment of the parenchyma, and partly to the zooxanthelle which are found in its enteric cells, each of which ordinarily contains one to three spherical parasitic alge 0:007—-0:009 mm. broad. This is the only known turbellarian in which zooxanthelle are found in the enteric cells, and which so far agrees with the Actiniz ; Hnterostoma has large pseudorhabdites in its integument, and four black eyes; it is extraordinarily sensitive to light. In the body-cavity of one individual there was found a young sexless Distomum, Anatomy and Histology of Myzostomida.t—Mr. F. Nausen has examined a few species of Myzostoma, of which M. aiganteum and M. * Zool. Anzeig., ix. (1886) pp. 338-42. + ‘Bidrag til Myzostomernes Anatomi og Histologi, 4to, Bergen, 1885, 80 pp. (9 pls.); English résumé, pp. 69-80. 620 SUMMARY OF CURRENT RESEARCHES RELATING TO graffi are new species, both taken from Antedon celtica. M. giganteuwm is very like M. gigas, but has a more robust and less flattened body ; M. graffi is like M. marginatum, but is distinguished by its “ tongue- indented margin,” and by the twenty cirri, one on each of the twenty tongues of the margin. The nervous system is altogether on the annelid and arthropod type, appears to be greatly differentiated, and to lie at some distance from the surface, the ventral cord being separated by a thick muscular layer from the ectoderm. The cerebral ganglion has no special sheath, but the circular commissures have a double neurilemma-sheath. The proboscidial nervous system is well developed, three pairs of nerves arising from the cesophageal ring and connecting it with the tentacular nerve-ring in the proboscis. The ventral cord is oblong, short, and concentrated, has a double nerve-sheath, and an intermediate nerve passing between the two longitudinal commissures; this communicates with the commissures by alternating branches. Eleven pairs of nerves issue from the ven- tral cord, five of which are larger than the other six: to Mr, Nausen the segmentation of the cord is not as obvious as it was to Mr. Beard. There is some difficulty in determining whether the so-called parapodial ganglia are really nervous, and not glandular in nature. In M. giganteum they were found to consist of two ganglia con- taining a large number of cells; these are multipolar, and each sends a prolongation towards the external extremity of the parapodium. In M. graffi the two ganglia of each parapodium are united, and contain a few (six to seven) gigantic cells. At the inferior extremity of the ganglion there is a peculiar organ which has the form of a glass bulb- receiver with the long receiver-neck passing towards the extremity of the parapodium; the globular portion consists of several concentric layers, within which there is a substance which appears to be coagulated. The outer neurilemma-sheath consists of a stout homogeneous membrane which stains deeply ; no nuclei were found in it, but many were seen adhering to its outer side; it is probably a cuticle, and is derived from the adjacent layers of connective tissue; it gives off septa which pass into the inner neurilemma by the inner parts of the ventral nerve-cord. The inner neurilemma-sheath is formed of re- ticulating layers of connective tissue, which form membranes for the fibrillar cords and the ganglionic cells. These last are mostly unipolar; the prolongations from them either pass directly into a peripheral nerve to form a nerve-tube, corresponding to the cylinder- axis of vertebrates, or they become broken up into the fibrillar reticulation of the central mass, from which nerve-tubes arise. In section, the protoplasm of the ganglion-cells always appear to be spongy. Direct division of the nuclei has been often observed in the ganglionic cells, but in no case karyokinesis. The author doubts the accuracy of Beard’s account of the development of the nervous system, and thinks that it is of the type common to Annelids. There does not appear to be a definite body-cavity, but rudiments of it are apparently to be found in the cavities in which the ova are ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621 situated. The body-parenchyma consists of a reticular nervous tissue, and the size of the meshes varies in different parts of the body. The nuclei of the muscular fibres are usually situated in proto- plasmic prominences at the side of each fibre; the fibres divide at their ends into several branches, between which there are protoplasmic remnants of, probably, connective tissue. What previous writers have called suckers are really ciliated glandular sacks; their walls are not, as Graff states, muscular, but they are glandular internally, and are covered by a ciliated cuticle, which has a striated appearance owing to the penetration of the cilia into the tissue. They differ from the nephridia of Annelids by not communicating with the body-cavity, but this may be explained by the degeneration or partial disappearance of the body-cavity ; their only point of resemblance to the segmental organs described by Huet in Isopods les in this want of an internal cavity. The hooks are solid, consisting of an outer homogeneous and an inner fibrous layer. In M. giganteum the glandular mass surrounding them is particularly well developed ; and its cavity communicates with the sea-water by the canal of the chief hook. The alimentary canal is divisible into the proboscidial canal with the cesophagus, the stomach, the intestinal branches from the stomach, and the rectum with the cloacal canal. Complemental males were found in M. giganteum, M. gigas, and M. carpenteri ; they are quite similar in structure to the hermaphro- dites, except that where the latter have ovaries the males have tubes with slightly developed cells, so that they have a certain resemblance to young ovaries; the dorsal oviduct (uterus) is feebly but the lateral oviducts are well developed. The author disagrees with Beard as to the secondary origin of the hermaphroditism of Myzostomida, inasmuch as the dicecious species are the most parasitic, and the rudiments of testes in M. cysticolum appear to be rather remnants of an androgynous stage than budding developments of male organs. As to the difficult question of the systematic position of the group, the author is of opinion that they are distinct from but allied to Cheetopods; while they show a tendency towards certain Arachnids (Linguatulida, Tardigrada, and perhaps Pycnogonida) and Crusta- ceans. They are sprung from the Trochophora, and, among Archi- annelids, are related to Histriodrilus. New Rotifer.*—Under the name of Stephanops leydigii Dr. O. Zacharias described a short time ago a new rotifer which has since been independently described by Mr. J. E. Lord. It is almost cer- tain that the species is distinct from the S. longispinatus of Tatem. New Floscule-;—Floscularia millsii resembles Stephanoceros in its elongated form and very attenuate lobes, as well as in its motion, but Dr. D. S. Kellicott regards it as belonging to the genus Floscu- laria on account of its general structure. The presence of a single * Zool. Auzeig., ix. (1886) pp. 318-20. + Proc, Amer. Soc. Micr., 8th Ann. Mecting, 1885, pp, 48-50 (1 fig.), 622 SUMMARY OF CURRENT RESEARCHES RELATING TO eye instead of two might warrant its place with Stephanoceros, but the arrangement of the cilia on the arms does not agree with that genus. ‘So far it has only been found in Black Creek, Ontario, attached to Ulricularia vulgaris. The gelatinous, sub-cylindrical sheaths of F. millsii are usually attached in the upper axil of a branch or leaf; it is usually solitary. The peduncle is short; the posterior attenuate ; the muscular part is long, and terminates in the broadly ovate body. The large mouth-funnel is but little broader at its free edge than below; the edge of the mouth is drawn out into fine, very long, flexible, trochal lobes, which are without the slightest knob-like enlargement at the extremity. One to three eggs are to be seen in the tube; but the author did not watch them till they were hatched, and therefore was unable to determine certainly as to which genus the animal should be referred. Echinodermata. Development of Comatula mediterranea,*—M. J. Barrois finds that the true blastopore of Comatula has nothing in common with what is ordinarily regarded as such; it closes before the end of development and at the time when the cells of the mesenchym are being formed at the expense of the endoderm. Immediately after its closure the endodermic vesicle is constricted into two parts; the two peritoneal sacs which are formed from the hinder portion do not change their places, but are transformed into two discs which unite around the intestine; these discs do not extend beyond the organ, and give off no prolongations either backwards or forwards ; the cord which is found in the stalk of the young pentacrinoid larva is formed exclusively from the mesenchym. ‘The vestibule or ten- tacular chamber is formed at the expense of the so-called blastopore ; this last is not an orifice destined to disappear, but a pit which appears late. When the larva becomes fixed this pit deepens, and gives rise by invagination to an entirely closed sac which makes its way between the ambulacral ring and the portion of the ectoderm which will form the dome of the calyx; here, as in Synapta, there is a displacement of the larval mouth, while the pit and the blastopore are the homologues of the mouth and anus of other larval echino- derms. Nerve-terminations, Sense-organs, and Glands in the Pedicel- larie of Echinids.t— Dr. O. Hamann has found and traced nerves in the various pedicellarie—buccal, trifoliate, tridactyle, and gemmi- form—in several specics of Echinids; and finds that from the main nerves branches are given off to sense-organs and glandular sacs. These sense-organs are elevations on the inner face of the valves of the pedicellariz in Hchinus acutus; there are two such sense-cleva- tions on each tube in the gemmiform pedicellariz. In Strongylocen- trotus lividus there is only one sense-elevation. In Sphzrechinus granularis there are three elevations near the * Comptes Rendus, cii. (1886) pp. 1176-7. + Ann. and Mag. Nat. Hist., xvii. (1886) pp. 469-72; from SB. Jenaisch, Gesell. f. Med. u. Naturwiss., 1886. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 623 base, and from them spring projections having the structure of the gustatory papille of vertebrates. In the tridactyle and buccal pedicellariz: the sense-cells are not collected into a sense-organ, but are scattered over the surface; and there are numerous nerve- fibrils running to the epithelium. The nerve-stems consist of fibres and ganglion-cells, which are more numerous at the point of branching of the nerves. In the gemmiform pedicellarie the valves contain one or two glandular sacs, with muscular walls, opening at the apex of the valve. All the pedicellarie are tactile organs, as the nerve-terminations indicate ; the trifoliate ones seem to remove sand and protozoa, &c., from the test. The larger pedicellarie serve to keep off larger living bodies, e. g. worms, and therefore act as weapons, as well as for organs of attachment when the animal is moving about. In #. microtuberculatus the gemmiform gland-bearing pedicellarie hold fast seaweeds, &c., when the animal is at rest; these help to hide it, and the secretion from the glands is therefore of the greatest service. Striated Muscles in the Echinida.*—In reference to Dr. O. Hamann’s description of the striated muscles in Echinids, Mr. F. E. Beddard draws attention to his own previous discovery of these muscles in 1881, in Hchinus sphera. Since then Mr. Beddard has found similar muscles in the pedicellariz of EH. melo and E. brevi- spinosus, Toxopneustes lividus, and in a species of Arbacia. He was unable to find these elements in the Echinids from the ‘ Challenger, probably owing to their bad state of preservation. He has also found, in the above species, the peculiar structures described by him and Mr. Geddes in EF. sphera; these have the form of flat plates of elastic tissue, in connection with the pedicel- larie. Development of Ophiopholis and Echinarachnius.t—Mr. J. Walter Fewkes finds that the larva of Ophiopholis aculeata passes through a pluteus-stage; the egg-cleavage is similar to that of other Echinoderms ; a gastrula is formed by the invagination of the blasto- derm, and consequently the stomach of the pluteus is an infolded wall of the blastoderm, and is not formed by delamination from the cells in the cavity; the mesoderm cells originate in two lateral clusters. The egg of Echinarachnius, which can be artificially fertilized, segments in the same way as that of other Echinoderms; it has no polar globules, while the egg is free in the water. As in some other Echinoderms the gastrula is formed by invagination ; the pluteus referred to Echinarachnius by A. Agassiz is an immature pluteus. The mode of development of the young on the water-tube of the pluteus resembles that of other Echinoids, and there is the same rosette form of the water-tubes. The first formed calcareous deposits of the test are trifid in shape and vary in number in different specimens. The extremity of each trifid division bifurcates later * Ann. and Mag. Nat. Hist., xvii. (1886) pp. 428-30. + Bull. Mus. Comp. Zool., xii. (1886) pp. 105-52 (8 pls.). 624 SUMMARY OF CURRENT RESEARCHES RELATING TO on, and the calcareous body thus formed appears to be enclosed in a transparent wall, which has a spherical outline. Spines are very early formed, and as in other Echinoderms are proportionately very large, as compared with those of the adult. Organization of Star-fishes.*—Prof. E. Perrier discovered in the collections from Cape Horn a new incubating star-fish, to which he gives the name of Asterias hyadesi; the young were found to be attached to the mother by a sort of lateral cord, which was inter- radial in position, and was formed by a prolongation of the buccal membrane. The youngest individuals were 2 mm. in diameter, and on their disc there were three calcareous pieces; M. Perrier thinks that this shows the incorrectness of the opinion of Messrs. Sladen and Carpenter that the ten primitive pieces of young asterids remain on the dise. The “ nervous layer” was found to be very poor in cells and to be nothing but a supporting membrane traversed throughout its thick- ness by a number of fibres; these end in certain cells of the external epithelium on the one hand, and on the other in the cells which have been considered as forming the internal epithelial layer; these cells are multipolar ; towards the end of the arm they cease to form a simple epithelial investment, and are supported by transverse trabecule which put them into relation with the cells of the sensory pits which are ordinarily regarded as eyes. These then are the nerve-cells, while the epithelial cells with which they are united across the supporting layer, ordinarily regarded as the true nervous system, are the sensory cells of the epithelium. On the wall of the sacciform canal which surrounds the hydro- phoral tube there is attached a problematic organ which is prolonged beyond the sacciform canal, in such a way as to form two organs connected with the intestine, and giving off two lateral branches which are in indirect relation with the genital glands. This proble- matic organ, which has lately been called the chromatogenous organ by Hamann, has in young Asterias hyadesi the form of a lateral conical prolongation of the peritoneal membrane of the digestive sac, and it contains a large number of vitelline bodies identical with those of the wall of the sac. The lobes of its surface are continuous with the trabeculae which form the living basis of the skeleton of the star- fish, and it dilates at its external surface into membranes which envelope the hydrophoral tube. This “ collateral organ ” of the tube is then not a heart, but the site of the production of elements, some of which, becoming free, form the corpuscles of the general cavity. The canaliculi of the madreporite are due to nothing more than the folding of the walls of the vibratile infundibulum, by which the hydrophoral tube opens to the exterior; M. Perrier is convinced that the tube communicates, at the point where it unites with the apex of the funnel, with the cavity of the sacciform canal. If the canaliculi of the madreporic plate only lead into the hydrophoral tube, or its upper expansion, the tube itself opens into the sacciform canal laterally, and sea water can thus pass into the lacunar spaces which * Comptes Rendus, cii. (1886) pp. 1146-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 625 Hamann considers as a schizoccel, into the subambulacral cavities, and into the general cavity. In star-fishes, then, as in Echinids and Comatulids, sea water plays an important physiological part, but its course is not regulated by as complicated a system of irrigating canals; this leads to a division of the Echinodermata into two great groups, one of which contains the Cystoidea, Blastoidea, Stellerida, and Ophiurida, and the other the Crinoids, Echinoids, and Holothurians. In this phylum, as in Coelen- terata and sponges, the penetration of water is a general phenomenon, while it is rare in worms, Arthropods, Mollusca, and Vertebrata; we may, therefore, with de Blainville, divide animals into the three great groups of Protozoa, Phytozoa, and Artiozoa. Vascular System of Spatangus purpureus.*—M. H. Prouho ascribes the difficulties in homologizing the vascular system of Spa- tangids with that of regular Echinids to the imperfect observation of certain anatomical facts. He finds that the two vascular systems of Spatangus are as distinct as in Hchinus, and their relations are exactly the same. The only difference is that, instead of there being a double Polian ring as in Cidaris, there is a double Polian canal. The sand- canal and the ovoid gland have exactly the same relations in Spatangus as in the regular forms. What has been called the sand-canal in Spatangus is really the homologue of the Polian ring of the Cidarida, and it is therefore proposed to call it the Polian canal. The term sand-canal or aquiferous tube must be reserved for the vessel which extends from this double canal to the posterior extremity of the ‘madreporite apophysis. Coelenterata. Origin of Metagenesis in Hydromeduse.t— Mr. W. K. Brooks considers that the view usually held, viz. that the sessile colony is the primitive form, from which medusw have been derived by division of labour and the specialization of the reproductive member of a polymorphic hydroid corm, is irreconcilable with the life-history of Narco- and Tracho-meduse. In Liriope amongst the latter, and in Aiginata and Cunina octo- naria amongst the former, a true planula, and a true hydra stage is passed through which developes directly into meduse. “The life- history of these forms proves conclusively that the medusa stage is older than the sessile hydroid-corm, which has arisen through the power to multiply asexually, which is possessed by the hydroid larva of the medusa.” By means of diagrams the life-history of various types is shown. Commencing with the above simple life-history, through that of C. parasitica, in which the actinula, or floating hydra, never becomes a medusa, but buds off hydrz which thus develope, he passes to the still more complicated instance of Turritopsis. Here the planula, * Comptes Rendus, cii. (1886) pp. 1498-1500. + Johns-Hopkins Univ. Cire., v. (1886) pp. 86-8. Ser, 2.— Vot. VI. 2-7 626 SUMMARY OF CURRENT RESEARCHES RELATING TO instead of becoming a hydra, becomes a degraded actinula, a mouth- less, untentaculated ‘‘ root”; this gives rise to hydra, which in turn produce medusa buds. In this form a secondary alternation is thus inserted in the life-history. In Hydractinia, owing to polymorphism, and to a much greater extent Podocoryne, a still more complicated history is gone through. The “root” buds off nutritive hydra, each of which buds off three sorts of polyps, one of which, the blastostyle, buds off meduse, which again bud off other meduse, which produce eggs. Here several secondary alternations are intercalated. The case of Hydractinia is regarded as beginning to simplify its life-history by the degradation of the sexual meduse into sessile reproductive organs. The author’s theory is that the remote ancestor of the Hydro- medus# was a solitary actinula with no medusa stage, but probably the power of budding. This actinula became more and more adapted to swimming until it became converted into a medusa, developing straight from the egg without alternation of generations. Having reached this stage, the larva acquired the property of fixing itself, and then multiplied by budding off similar larve, which became meduse. This fixed condition having become perpetuated by natural selection, the primary larva ceased to become a medusa, but remained a sessile larva and budded off larvee which became sexual medusz. The medusa characteristics of these secondary larvee became accele- rated, and the primary larva acquired the power to produce larve which like itself remained sessile. In this way sessile hydra com- munities with medusa buds and free sexual meduse were evolved ; finally these became polymorphic ; and gradually the free meduse were degraded to medusa-buds or sexual buds on the bodies of the sessile hydras. Nematocysts in the Siphonophora.*—M. M. Bedot finds in the Velellide two sorts of cnidoblasts, provided with stalks (‘“ tiges”’), the nematocysts of which are distinguished by the presence or absence of a barb at the base of the thread, as well as by their difference in size. In the large cnidoblasts, muscular striations are seen at the base of the stalk; this also shows at its terminal region a spindle- shaped organ, which encloses a spirally coiled filament and a highly refracting spherical body. The cnidoblasts which are scattered through the ectoderm of the tentacles in the Velellide and which are not grouped to form batteries are deprived of stalks and cnidocils. The Physalide also present two forms of nematocysts, neither of which are barbed. On the fishing filaments there is every stage between cnidoblasts with and without a stalk. From this one is led to conclude that the stalk is formed from the enidoblast itself, and not from a neighbouring cell, as was supposed. The nematocyst arises in the interior of a small spherical cavity, which has become formed in the enidoblast, and which is filled with a transparent fluid. From the wall of this cavity a small bud or “ nematoblast ” arises which gradually projects into the fluid. It increases greatly and ultimately nearly * Arch. Sci. Phys. et Nat., xv. (1886) pp. 415-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 627 fills the cavity and is only united to the wall by a narrow stalk. The nematoblast gives rise to the thread; the fluid which surrounds it solidifies and forms the case of the nematocyst. When the thread is barbed its development is more complicated; in the interior of the nematoblast a small sphere appears, this becomes hollow and invagi- nated, and thus forms the barb. Stephanotrochus moseleyanus.*—Mr. W. L. Sclater describes a new species of the genus Stephanetrochus, which is not only interest- ing as being the finest and largest of the genus, but as the first recorded from the British seas ; it was dredged by H.M.S. ‘ Triton’ at a depth of 570 fathoms in lat. 59° 51’ N. and long. 8° 18’ W.; its nearest allies were taken by the ‘ Challenger ’ off the Azores and Pernambuco. It differs from species already described by the greater development of the pal, and the stouter primary and secondary septa, of which there are altogether five complete cycles. The cord presents evidence in favour of Koch’s theory that the theca is formed from the fused peripheral ends of the septa; the darkly coloured oral disc, the ‘tentacles, and outer soft wall contains polyperythrin ; the tentacles are in four cycles, and those of the innermost are the largest and twelve in number. In the arrangement of the muscles on the mesenteries Stephanotrochus exactly corresponds to the Hexactinian type, as do all other madrepores that have yet been studied. The single specimen examined contained ova only, so that the species is probably diccious, Cells, which appear to be calycoblasts, differ from those described by Koch in having an irregular instead of a quadrangular shape; this may be due to their greater age. Polyparium ambulans.{|—Dr. A. Korotneff describes from the straits near the island of Billiton, a remarkable colony, 7 em. long by 15 em. broad, which is bandlike in form, and on one side has the upper sharply separated from the lower surface; on the other side, however, they pass into one another; the anterior is not to be distinguished from the hinder end. The upper surface is covered by peculiar polyps, the base of each of which is much broader than the tip, which carries a round orifice. The polyps appear to be altogether devoid of tentacles ; They are not all of the same size, and the smallest, which have no oral orifice, appear to be buds. The lower surface is covered with suckers, which are very regularly arranged; each row is set transversely, and is separated from its neighbours by a transverse groove ; the suckers, like the polyps, vary considerably in size ; the whole colony moves like Cristatella. The polyps have no septa, and the internal surface is quite smooth and devoid of the ridges which might indicate an affinity with corals. The lumen of each polyp passes into the spacious lumen of the foot or body of the whole colony; this is broken up by partitions into divisions of equal size, but these partitions are certainly not the homologues of the ordinary septa of polyps; they are set transversely te * Proc. Zool. Soc., 1886, pp. 128-36 (3 pls.). + Zool, Anzeig., ix. (1886) pp. 220-4. ; aes 628 SUMMARY OF CURRENT RESEARCHES RELATING TO the longitudinal axis, and divide the cavity in such a way that every two segments enclose a lumen which opens above and to the exterior by means of the polyps and carries below a row of suckers. Each polyp has a corresponding sucker, and we may, therefore, regard each polyp plus a sucker, as one individual. Each sucker has a retort-shaped cavity which communicates with the lumen of the colony. ‘Typically each polyp resembles an Actinian in minute structure. Cells and fibres unite to form a continuous nervous sheath. The endodermal cells are completely filled with parasitic plant-cells. There are no radial or circular muscular fibres in the suckers, and they repeat the general type of structure, with the exception that glands are developed in them; the septa have a double musculature ; when their longitudinal fibres contract the foot with the suckers is withdrawn from the ground, and the transverse row of suckers which correspond to the partition are set free. The transverse system of muscles next contracts, and the whole colony becomes longer along its long axis; in this way the movement of the colony is effected. Porifera. Sponge Spicules.*—Prof. W. J. Sollas discusses the possibility of siliceous sponge spicules being transformed into calcareous spicules, as has happened in fossil sponges. He finds the siliceous spicules are composed, not of pure silica, like quartz, but of a colloid variety, combined with organic material. In order to determine the refractive index of these spicules, they should be placed in some fluid in which they become invisible, that is in a fluid of the same refractive index. The fluid in this case was chloroform, the index of which is 1°449 ; thus these spicules are composed of a substance with very nearly the same index as opal. By this method similar species of minerals can be distinguished when isotropic; and even anisotropic substances can be so distinguished, by using, in conjunction, Nicol’s prisms. In the case of fossil calcareous sponges, their preservation or not depends on their being composed of calcite or arragonite or some combination of either with organic substances. In order to ascertain the specific gravity of sponge spicules, the author adopted a method which is described at p. 879, Vol. V. of this Journal. From his experiments he considers them to be probably calcite in combination with organic matter, their specific gravity being 2:62. The author disputes Hackel’s view that regular triradiate spicules have a crystalline form, derived from a regular 12-sided pyramid ; he finds that the optic axes of a sagittal spicule and the morphological axis of the unpaired ray are in the same plane, which is a right angle to the plane of the spicule. From other experiments with crossed nicols he concludes that the acerate is not homologous with the unpaired ray, but with one or both of the paired rays, of a sagittal spicule. Calcareous spicules, after remaining in Canada balsam for some * Scientif. Proc. R. Dublin Soc., iv. (1885) pp. 374-92 (1 pl. and 7 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 629 years, were found to be etched with striz, ending in edges transverse to them; and near the apex of a spicule the projecting angles of crystals are seen. In the case of sagittal spicules the paired rays are etched, the unpaired is not affected. The author was able to produce the etching, at will, by means of acetic acid. In section acerates are oval or rhomboidal, and this serves to distinguish calca- reous from siliceous spicules. This fact is an argument in favour of Prof. Sollas’s opinion that the Pharetrones are of a calcareous nature. He concludes that the acerates of Calcispongie are built up of excessively elongated primitive rhombohedrons of calcite. The perforate Foraminifera consist of calcite, judging from their specific gravity ; whilst the Imperforata consist either of arragonite, or if of calcite, this must be in combination with phosphate of lime, or carbonate of iron. Artificial deposition of Crystals of Calcite on Spicules of Calci- sponge.*—Prof. W. J. Sollas mentions the finding of sponge spicules jncrusted with crystals of calcite, after standing for some days in water containing an excess of calcium carbonate. They appeared to have their optic axes orientated similarly to the calcite of the spicule. Tn a sagittal triradiate the crystals are confined to opposite sides of the paired ray, and to the extremity of the unpaired ray. In an acerate opposite sides for the whole length were incrusted; thus the crystals are deposited on the parts showing greatest liability to solution, and the polarity which leads to solution appears to deter- mine deposition. Sponges of Bohemia.j—Herr P. Frantisék gives an account of various sponges. The firstis Carterius stefanowii, which varies in size, but may be 10 cm. long and 3 cm. broad ; the spicules are ordinarily quite smooth and sharp at their tips; the gemmules are spherical or ellipsoidal, and have a high upper pole. The germ is protected by an internal chitinous membrane, from which arises a cylindrical or conical air-tube; at its end there is a delicate crown-like appendage. The inner membrane is covered by an air-chamber-layer, which consists of small polygonal chambers, which are normally filled with air. The amphidiscs are very numerous, and are provided with a number of spines; they are of two lengths, the longer of which, with the crown at the upper end of the air-tube, forms an apparatus by means of which the gemmules can attach themselves to foreign bodies, and so be carried from place to place. This species was first found in Russia by Dybowski, who, with a query, called it Dossilia stefanowit. Ephydatia bohemica n. sp. is found with Euspongilla lacustris ; it is closely allied to C. stefanowii, but the gemmules have no air-tube, and the amphidises are all of the same length. ‘The author has notes on Spongilla fragilis, Ephydatia muelleri, and Euspongilla jordanensis. * Scientif. Proc. R. Dublin Soc., v. (1886) p. 73. + SB. K. Bohm. Ges. Wiss., 1886, pp. 147-74—German abstract, pp. 169-74 (1 pl.). 630 SUMMARY OF CURRENT RESEARCHES RELATING TO Classification of Sponges.*—Prof. W. J. Sollas gives the following classification of the phylum Porifera :— Class I. Plethospongia. Sub-class 1. Hexactinellida. Order 1. Lyssakina. Order 2. Dictyonina. Sub-class 2. Demospongia. Tribe a. Monaxida. Order 1. Monaxona. Order 2. Ceratosa. Tribe b. Tetractinellida. Order 1. Choristida. Order 2. Lithistida. Sub-class 3. Myxospongia. Order 1. Halisarcosa. Order 2. Chondrosiosa. Class II. Calcispongie. Protozoa. Physiology and Biology of Protozoa.;—Dr. A. Gruber gives an account of his observations on artificial divisibility and regeneration in Protozoa. He has chiefly made use of the large Stentor ceruleus ; here, as in Oxytricha, the anterior end replaces the lost posterior end, and the right side the lost left side, and vice versé. He finds that the regeneration of the organula follows the same course as their new formation in spontaneous fission. The unknown impulse which induces the animals to divide, and the irritation caused by the violent removal of a part of the body, are identical in their effects. If we ascribe regeneration in the Metazoa to the influence of embryonally formed cells, we must in the Protozoa ascribe the function of new formative elements to originally formed elementary particles (“micella”) which are subject to the directing influence of the nucleus. Regeneration is due only to a conversion of elementary parts already present, and is set up by external irritation; it takes place rapidly, and in the Stentor is very powerful ; no particular part of the body appears to be specially disposed thereto, but all parts react in the same way. The author relates experiments which justify these conclusions, and next describes others which show that two artificially produced halves are able to increase spontaneously at exactly the same time, although after section they were apparently not equivalent; thus, in one case, the anterior portion which still possessed the peristomial area, mouth, and cesophagus had only to go through the process of wound-healing, while the posterior portion had to produce all the organs anew; the latter was, nevertheless, able to answer to the impulse just as quickly as the former. This observation shows also that the material for new formations in the Infusoria is not stored * Scientif. Proc. R. Dublin Soc., v. (1885) p. 112. ~ Ber. Naturf. Ges. zu Freiburg i. B., i. (1886) Heft 2; translated Ann. and Mag. Nat. Hist., xvii. (1886) pp. 473-94. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 631 up as such, but that the primitive elementary parts are convertible at any time. Other infusorians did not give as striking results as Stentor czruleus, but Dr. Gruber thinks that the difference depends on the greater or less faculty of existing under conditions which are not quite natural, and that the power of replacing lost parts is proper to all Protozoa. This remarkable acquisition of the regenerative faculty may depend on the fact that Protozoa frequently break up spontaneously into irregular fragments, and that many of these frag- ments are capable of again being developed into normal animals. The author next proceeds to discuss the significance of the nucleus in regeneration; the want of the nucleus brings about an incapacity to replace lost parts, or produce new structures, and it is clear that the nucleus is the most important, and the species-preservative con- stituent of the cell, and to it we justly ascribe the highest importance in the processes of fecundation and inheritance. A study of Ameba binucleata showed that though the chromatic substance of the nuclei varies considerably in form and arrangement, the true nuclei of any one specimen always agree; this seems to show that the chromatin in the nucleus is an important factor and is not merely an accumu- lation of nutritive material. The observation of the phenomena of spontaneous division led to the discovery of certain small differences between the daughter- individuals, and this appears to indicate that the morphological and physiological congruency of the two daughter-individuals produced by division is by no means quite absolute. In Stentor division ordinarily took place at intervals of two days, and the presence or absence of nutrient material had no influence on the time of the division. Of this spontaneous division two kinds may be distinguished among Infusoria; one occurs when the individual has grown to a certain size which cannot be exceeded; the other is by divisions follow- ing on one another rapidly, and in definite intervals of time, without intervening growth; this, of course, is combined with continual decrease in the size of the body, and happens when the infusorian is placed under unfavourable conditions, in which it is desirable to rapidly produce a large number of individuals for the preservation of the species. These hurried divisions are succeeded by a period of conjugation. The behaviour of infusorians during conjugation throws some light on the nature of the nervous elements in the cell; as Gruber has already stated, the two members of a pair in copuld make exactly concordant movements so long as they are still united by a bridge of protoplasm. As a single thread-like bridge of protoplasm suffices to cause the loosely connected pieces to behave as one individual, it is clear that the nervous functions in the infusorial body are not confined to definite courses, and that the exertion of will uniformly governs every protoplasmic element. In other words, the nervous potency of the cell is diffused. The consentaneous action of the individuals of a protozoic colony is due to the fact that they are united to one another by cords of protoplasm. The seat of the diffused nervous potency is chiefly to be sought for in the cortex. 632 SUMMARY OF CURRENT RESEARCHES RELATING ‘TO Morphology of Vorticelline and allied Ciliata.* — Prof. O. Biitschli discusses the problem of the process of division in the Vor- ticelline, which appears to differ so much from what is found in allied Ciliata; it being, as we know, longitudinal instead of transverse, as it is in most other forms. The suggestion arises that the difference is not real, but is dependent on an incorrect morphological orientation of the Vorticelline body. By the Vorticelline the author means the groups which Stein called Vorticellina, Ophrydina, and Urceo- larina; they agree with all other ciliates (except the so-called Holotricha) in having an adoral zone of stronger cilia, which, as a rule, follows this course—the mouth is at some distance from the anterior end of the body, is on the aspect which is called ventral, and is frequently somewhat nearer to the left than the right side. From it the zone extends to the left margin of a so-called peri- stomial area, which generally corresponds to the left margin of the ventral side, as far as the anterior end; if it is well developed, as is generally the case, it bends round to the right, and extends along the right side of the ventral surface, more or less far back. The zone takes a more or less well-marked spiral course which is especially well seen in some Heterotricha (Stentor and others). This adoral spiral in the Vorticellina has considerable resemblance to that of a Stentor, but is especially distinguished by the fact that it appears to coil to the right and not to the left. As to the origin of the Vorticellina, Prof. Biitschli thinks it un- necessary to take into consideration the restriction of cilia to the ciliated zone, as he believes that this character has been acquired within the limits of the group. On the other hand, it is quite clear that the fixed have been derived from free-swimming forms. The most primitive forms appear to be the Urceolarina, which have a relatively simple peristomial structure, and among them the genus Licnophora ; the surface of its attaching disc is in a plane with the peristome ; the hinder half of the body appears as a kind of stalk for the disc. It seems to Prof. Biitschli that this form can without difficulty be derived from the other Ciliata, whether hypo- or hetero- trichous. From an ectopirasitic infusorian, provided with a mouth- spiral, which moves about by its ventral surface on the integument of the animal on which it dwells, Licnophora may be derived by sup- posing that the ciliation became specialized into the ciliated circlet. The hinder part of the ventral surface gradually developed into a special dise of attachment, whereby the anterior part of the body, with the spiral and the mouth, became emancipated from their inferior position ; the mode of life of Kerona polyporum shows that this is not a fanciful sketch. If the author’s views are correct, the so-called ciliated organ of the Vorticelline must be regarded as the dorsal side, and all the rest of the body as ventral; in this case the point from which the stalk of the fixed forms arises must be regarded as the middle point of the ventral surface. With this new orientation we are able to explain * Morphol. Jahrb., xi. (1886) pp. 503-65. ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 633 the apparently anomalous manner of division in the Vorticellinw. The author gives an account of his observations on division, and con- cludes with some notes on Lagenophrys, in which Stein reported that fission was in an oblique direction. Prof. Biitschli suggests that this appearance is due to the abnormal course taken by the adoral spiral. Species of Chromulina as Stages of Palmella.*—Herr N. Wille describes the life-history of Chrysopyxis which, when it begins its spring vegetation, leaves the thick membrane which invests the eucysted cell, and multiplies by transverse division within a mucous covering; while the cells are still within this coat the cilia may be seen to be moving; at the anterior end of the body there is a con- tractile vacuole. A species of Chromophyton is next described, which has oviform swarm-spores, and appears to develope into an EHpipyzis ; they may be easily distinguished from Chrysopyxis by having their contractile vacuole in the centre of the cell. The mode of develop- ment of these two forms is so similar to that of a Dinobryon that the author thinks they must be placed in the same family ; and he is ‘further of opinion that the swarm-spores of Chrysopyxis are identical with the round form of Chromophyton Rosanoffii and Monas ochracea, and that those of Dinobryon (Epipyxis) are the same as the oviform stages of C. Rosanoffii and Monas flavicans ; their reported presence in the same waters justifies this view. Microscopic Pelagic Animals of the Mediterranean.t—Dr. O. E. Imhof describes a new species of Cyttarocylis—C. adriatica—the test of which has the form of a stalked cup, the stalk, however, not serving as part of the habitation. A species of Codonella was found near Brindisi which resembles C. acuminata of the Lake of Como, but differs in size—the whole length was 0°176 mm. New Fresh-water Infusoria.t—Dr. A. C. Stokes adds several new species to his former contributions. Physomonas elongata differs from previous species in the absence of the subspherical outline usually considered characteristic of the genus. A pedicle is formed temporarily, though the animal is usually free-swimming. Reproduction takes place by longitudinal fission. Tetramitus variabilis is noticeable for the entire absence of the longitudinal grooves found in the other species. Urceolus subulosus has a cuticular investment of sand, which is apparently unique among Infusorians. This obscures the internal structure. Chrysopyais triangularis, C. macrotrachela, and C. ampullacea have forms signified by the names given to them. Prorodon limnetis differs from P. teres, which it most nearly approaches, in the excentric position of the mouth, and the well-marked anterolateral curvature. Trachelophyllum clavatum is the only species which possesses a single nucleus. * Bot. Centralbl , xxiii. (1885) pp. 258-63. + Zool. Anzeig., ix. (1886) pp. 198-200. } Amer. Mon. Micr. J ourn., vil. (1886) pp. 81-6 (18 figs.). 634 SUMMARY OF CURRENT RESEARCHES RELATING TO Perispira strophosoma bears a ciliated ridge-like spiral elevation across the anterior part of body. Lacrymaria teres differs from L. truncata chiefly in the possession of complex contractile vacuoles, of which there are two spherical ones, connected by a narrow tortuous canal; also in the absence of the convoluted nucleus. Leucophrys curvilata contains no chlorophyll found in L. emarginata Stokes. Strombidinopsis acuminata has at the posterior end of the body a pointed process ; the anterior ciliary wreath is circular. Vorticella floridensis has a campanulate body which can change its form by elongation or compression. Cothurnia canthocampi differs from C. astaci in the absence of the eversion of the anterior border, and in the very short distance to which the expanded zooid extends beyond the lorica. Fresh-water Infusoria.*— Referring to the encystment of Rotifers during the slow drying up of ponds, merely for protection, Dr. D. 8. Kellicott remarks that the same ‘ protective ” encystment in Infusoria must not be confounded with “duplicative” or with “ sporular” encystment, previous to fission or to division into spores. ‘The author considers that Vorticella brevistyla @Udekem, V. rhabdostyloides Kell., are synonymous with Spastostyla sertulariwm. Geza Enty formed the genus for Vorticellids in which the upper part of the stalk is flexible. The cyst of the species is oval. Amphileptus meleagris forms its cyst upon the stalk of Opercularia nutans after devouring it; and he also found numerous cysts on the thick pedicels of O. rugosa. While encysted Amphileptus divides into two bodies, which escape as ciliated forms, similar to but smaller than the parent. He notices the internal budding of Podophrya quadripartita, but was unable to confirm Biitschli’s account of the change in the nucleus from a granular to a fibrillated condition. In another communication f Dr. Kellicott mentions the peculiar Vorticellid Epistylis ophidioidea in which, besides the ordinary individuals, there are, in a colony, a few elongated snakelike forms, which he regards as having some relation to reproduction. This species has been recently taken in the deep water of Niagara. Amongst the Tentaculifera, the following new forms are described :-— Acineta cuspidata has a spheroidal body which does not quite - fill the shortly-pedunculated lorica. There are only a few tentacles, which are long, flexible, and slightly thickened at the extremity. The edge of the lorica is raised up into a point on each side between the two groups of tentacles. This species is closely allied to the marine A. dibdalteria. A. flava has a triangular compressed lorica, with a slender pedicle, which is flexible just below the lorica. The body is not adherent. The tentacles are few, short and distinctly capitate. * The Microscope, vi. (1886) pp. 53-8 (4 figs.). + Proc. Amer. Soc, Mier., 8th Ann. Meeting, 1885, pp. 38-47 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 635 The colour is usually yellowish-brown when the animal is attached to Stephanodiscus niagare, but sometimes green, when on Cladophora glomerata; this latter condition is regarded as a young stage. In Podophrya diaptomi the body is pyriform, elongate, with transparent protoplasm, the granules in which are larger anteriorly than posteriorly. The numerous tentacles are not distinctly capitate and are arranged in three fascicles. The nucleus is spheroidal. The young are nearly spherical and the tentacles are then arranged irregularly. The animal is usually attached to the under side of the body-rings of its host, Diaptomus sp. Platycola intermedia is now regarded by the author as a species distinct from P. longicollis with which he previously placed it as a variety; his reasons are founded on the shorter and not funnel-shaped neck. Amongst the Ciliata he describes as new species :—LEpistylis cambari, which is found on the gills of various species of Cam- barus in Niagara river. The body is broadest in the middle and somewhat attenuate posteriorly. The disc is narrow, the peristome thickened. The stout pedicle is bent in large colonies, and usually branches on one side only. By the shape of its disc it is allied to Umbilicata, but the different form of the body and pedicle clearly separate them. Vorticella rhabdostyloides has a nearly globular body, peristome thickened, nucleus thick and but slightly curved. This species was found plentifully in Niagara, attached to Stephanodiscus Niagare and other diatoms. Gerda sigmoides was usually found in pairs; the body is very flexible; the posterior tapers nearly to a point, the anterior is grace- fully curved. Mesodinium recurvum has a globose body, with only a short snout- like process. At about one-third the length of the body is a girdle of cilia bent backwards; above this is a wreath of long cilia. It closely resembles Halteria volvox in its jumping action. Strombidium oblongum, and Trachelomonas torta, are other new forms described. A new genus, Diplostyla, is formed from a species, D. inhesa, found in swamp water among alge at Point Abino, Ontario. It inhabits an ovate membranous tube, open at both ends; the body does not protrude, but water passing through the tube carries the food to the animal, and in this seems to resemble Oxytricha tubicola. The body cilia are fine and long; mouth behind the centre of the body ; undulating membrane long; adoral cilia stronger than body cilia; posteriorly some setose cilia ; budding was observed. Parasites of the Blood.* Prof. B. Danilewsky describes a number of Hamatozoa observed by him during his study of blood- parasites. With the exception of Bacteria and Vermes the parasites probably all belong either to the Sporozoa or to the Flagellata. As to their entrance into the vascular system, Prof. Danilewsky supports the theory that an important part in the transport (from the ali- * Biol. Centralbl., v. (1885) pp. 529-37. 636 SUMMARY OF CURRENT RESEARCHES RELATING TO mentary canal to the blood-vessels) is played by the leucocytes, an hypothesis confirmed by the occurrence of Hemocytozoa or parasites within the red blood-corpuscles, while within the leucocytes bodies are not unfrequently observed which resemble parasitic germs. I. Trypanosoma sanguinis Gruby. This Flagellate was found in as many as six varieties in the blood of frogs and fishes. The cha- racteristic undulating hyaline membrane, prolonged into a flagellum, displayed various degrees of differentiation. All Trypanosoma species exhibit screw-like undulating movements and contractions. In the frog the following four varieties are distinguishable: (1) the simple membranous form, in which the flat extremely mobile body passes without visible boundary into the membrane ; (2) the rolled- up form, having a filter-like shape, resulting from the helicoid twisting of the body on its transverse axis ; the undulating membrane extends along the superior broader margin; (3) the “ flat-spiral ” form, having a somewhat compressed long conical body, pointed posteriorly and spirally twisted; the undulating membrane only along the anterior broader flattened end; (4) the “comb-like spiral” form, twisted in a more or less complete longitudinal spiral, with the surface of the pear-shaped body like a Pecten shell; the narrow, well-differentiated undulating membrane along one margin or in the cleft between the two approximated margins. If the two margins of the leaf-like body are fused there is, of course, no cleft; the mem- brane arises from the anterior broad end, and a most beautiful “cornucopia” form results. These varieties of Trypanosoma (Undulo-Flagellata) were not observed to pass into one another, though less defined, possibly inter- mediate forms were seen. In preparations where the blood was at rest, interesting changes of cell-phase were observed; the first form became spherical, the flagellum grew enormously at the expense of the membrane, and was finally broken off, leaving an ameeboid mass, which occasionally formed long pseudopodia. (‘There was thus a passage from the ciliated to the amceboid phase of the “ cell-cycle” emphasized by Geddes.) In similar circumstances the third form was observed to retract membrane and flagellum, and to exhibit nuclear division resulting in the formation of a mass of (sixty-four) spores. These became modified into monad-like forms, gradually differentiating, and exhibiting longitudinal fission. A_ transverse direct division of the first form is also described, and Prof. Danilewsky also observed the formation of buds, without, however, being able to follow out their history. Trypanosoma piscium is much smaller and rarer than that of the frog, &c., and occurs in two distinct forms: (a) simple, narrow, and thread-like, with no undulating membrane distinct from the body, and exhibiting extraordinarily lively movements; (b) spindle-shaped, consisting of a more or less stiff body and a relatively narrow mem- brane, spirally twisted from one end to the other and continued directly into the undulating flagellum. Prof. Danilewsky notes the highly developed plasticity of these Hzematozoa, especially of the fourth variety of T. sanguinis, which in ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 637 artificial cultivations (albuminous solutions, &e.) exhibits manifold variations of form, and often produces numerous mobile processes. II. Hematozoa of Lizards. Within the red blood-corpuscles of Lacerta viridis three different forms were distinguished: (1) a quiescent worm-like cytozoon, resembling Heemogregarina Step, lying near the nucleus of degenerating corpuscles ; (2) a smaller mobile form, within almost normal hemocytes, and characterized by a number of strongly refracting round granules at each end of the otherwise clear worm- like body ; (3) a larger form, with one end distinctly thicker, occur- ring free in the blood as well as within the corpuscles. These varieties are connected by intermediate forms, and the differences probably depend on age and nutritive conditions. Ill. Hematozoa of Birds. (1) A form resembling Hemogre- garina, about the length of a red blood-corpuscle, with a screw-like motion, usually with one end rounded and the other more pointed, and exhibiting a vesicular nucleus within the blueish-grey, homo- geneous strongly refracting body, was observed swimming free in the plasma. (2) A second, much longer form very closely resembled Trypanosoma fusiforme piscium. (3) A third Hematozoon occurs frequently within the red blood-corpuscles as a “ pseudovacuole” of variable shape, which increases in size, assumes a spherical form, and causes the disintegration of the hemocytes. It eventually liberates itself, and is seen rotating rapidly in the plasma by means of its flagellum. iE DODANY. A. GENERAL, including the Anatomy and Physiology, of the Phanerogamia. a. Anatomy.* Plasmolytic Studies of the Membrane of Vacuoles.;—Dr. H. de Vries has made a large number of observations on the nature of the membrane—for which he proposes the term tonoplast—which separates a vacuole from the surrounding protoplasm. Coincident results were obtained from a large number of plants, the one best adapted for the purpose being Spirogyra nitida. The following is a summary of the more important. It is universally the case in the vegetable kingdom, and in the most various forms of tissue, that the vacuoles possess a true mem- brane, which may readily be made visible by the application of a 10 per cent. solution of potassium nitrate with the assistance of eosin; the tonoplast being more resistent to the action of this reagent * This subdivision contains (1) Cell-structure and Protoplasm (including the Nucleus and Cell-division; (2) Other Cell-contents (including the Cell-sap and Chlorophyll); (3) Secretions; (4) Structure of Tissues; and (5) Structure of Organs. z Pringsheim’s Jahrb. f. Wiss. Bot., xvi. (1885) pp. 465-598 (4 pls.). 638 SUMMARY OF CURRENT RESEARCHES RELATING TO than the rest of the protoplasm, and retaining its normal properties for hours, and even days, after the latter has been killed. 'This pro- perty indicates a greater density of its substance. The tonoplast is a sharply defined membrane which detaches itself smoothly from the rest of the protoplasm. Application of 10 per cent. nitrate-solution causes normal plasmolysis ; the outer protoplasm loses its tension, and takes the cosin-staining, while the vacuole remains colourless and its tonoplast in a state of tension. In Spirogyra-cells the outer proto- plasm was commonly ruptured, and, by its contraction, partially or entirely expelled the vacuole. The vacuoles contract into a larger or smaller number of free globular vesicles within the stiffened protoplasm-body. The tonoplast agrees with the rest of the protoplasm, and especially with the parietal layer, in their most important properties, both in normal physiological functions and in behaviour to plasmolytice and other reagents. It agrees with the parietal layer in being scarcely or not at all permeable, protecting in this way the enclosed portions of the protoplasts. They both excrete certain definite substances from their surface, whether stored up in the solid condition like cellulose, or dissolved in the cell-sap like organic acids. In certain cases, asin plasmodia, and in the central circulating movement, both act as motile organs. It is possible in some cases to press out the vacuoles through small openings in the stiffened protoplasm around them ; and they then behave like swarmspores. When vacuoles are isolated from the surrounding protoplasm, their tonoplasts are from the first permeable for acids and bases, but not for easily diffusible salts like potassium nitrate. But after a vacuole has remained for some days in this solution, it is more or less permeable for sodium chloride and potassium nitrate; and this is the case to a greater degree if it was treated at first with a dilute solution of any poison. All experiments indicate that after the death of the outer protoplasm, the tonoplasts do not become suddenly permeable, but only gradually. This increase of permeability depends there- fore on a molecular change, and not on the formation of fissures. In a criticism on De Vries’s paper, Herr W. Pfeffer * agrees in the main with his conclusions ; and finds a very serviceable staining reagent for the purpose in a 0:001--002 per cent. solution of methyl- blue. From a mixture of 1 part of methyl-blue and 10,000,000 parts water, the root-hairs of Trianea, Lemna, and Azolla will, in a few days, absorb the pigment as completely as from a concentrated solu- tion. Methyl-violet is absorbed in the same way, without injury to the currents and other vital phenomena of the protoplasm. Nigrosin and anilin-blue, on the other hand, are not taken up in the same way by the living cell. Aggregation of Protoplasm in Drosera. t—According to Dr. H. de Vries, the phenomenon described by Darwin as “ aggregation of protoplasm” is in reality due to contraction and division of the * Bot. Ztg., xliv. (1886) pp. 114-25. + Ibid., pp. 1-11, 17-26, 33-48, 57-64 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 639 vacuoles. He demonstrated that the vacuoles are enclosed in a definite membrane * by the application of a 10 per cent. solution of potassium nitrate, which kills the rest of the protoplasm without bringing about any change in the membrane of the vacuoles. The “agoregated masses” are in reality vesicles filled by fluid contents, each vesicle being a part of a vacuole with its enclosed cell-sap. The irritation which excites Drosera and other insectivorous plants to an increased development of their secretion, brings about peculiar and very active movements in the cells of the tentacles, and of their stalks. These movements consist chiefly of three factors, viz.:—(1) An in- ereased and much more strongly differentiated circulation of the parietal protoplasm ; (2) A division of the vacuoles into a larger or smaller number of portions, each of which is enclosed in a part of the original membrane of the vacuole; (3) A very considerable diminution of the volume of these vacuoles, a portion of their mass being expelled through the membrane and collecting between it and the circulating protoplasm. This expelled fluid possesses, at least approximately, the same attractive force for water as the rest, but a different chemical composition, the pigment and certain dissolved albuminous substances not being expelled along with it. These albuminous substances can be separated by means of ammonia salts in the form of a finely granular precipitate, which gradually collects into larger balls, and is at first soft but afterwards harder ; but this does not take place in the normal process of aggregation. When the action of the irritant ceases, the cells gradually return to their original condition, the vacuoles again increasing and coalescing. The observations were made chiefly on the marginal tentacles of the leaves of Drosera rotundifolia ; also on D. intermedia and spathulata, and on Pinguicula vulgaris. The substance used for exciting the irritation was small particles of white of egg. Influence of Mechanical Forces on Cell-division, &c.+—Accord- ing to researches by Herr R. Hoffmann, a unilateral strong positive pressure on the cambium-cells may check or even prevent growth in the direction opposed to the pressure. If the pressure acts obliquely on the dividing cells the rows of cells deviate from their normal position. When the bark-pressure has not only disappeared, but become negative, as in depressions in the surface of the stem where the tension of the bark is uniform, the cell-divisions appear to increase in frequency, young stems becoming cylindrical instead of angular. When a stem is wounded, the normal pressure of the bark is removed from the cambium, causing a stronger growth of the stem in the neighbourhood of the wound ; and the cells formed on the margins of wounds are isodiametrical until the normal conditions of pressure are restored. The cause of the lateral growth of cortical cells on a wound is traced in the same way. * Cf. supra, p. 637. + Hoffmann, R., ‘Unters. iiber die Wirkung mechanischer Krafte auf die Theilimg u.s. w. der Zellen, 24 pp. (4 pls.), Berlin, 1885. See Bot. Centralbl., Xxy. (1886) p. 359. 640 SUMMARY OF CURRENT RESEARCHES RELATING TO Chlorophyll - grains and Chromatophores.*—Dr. A. F. W. Schimper publishes a very exhaustive treatise on this subject con- taining details of fresh observations and a résumé of the work of other observers. The nucleus is wanting in no living vegetable cells, with the doubtful exception of the Schizomycetes ; in addition to the nucleus are other protoplasmic structures, known as chromatophores, from their capacity of producing pigments. They are formed exclusively from chromatophores previously in existence, never by new formation from the cell-protoplasm. The author has detected these structures in the ovum-cell and embryo-sac of Hyacinthus non-scriptus, Daphne Blagyana, and Torenia asiatica, and in the ovum-cell of Atrichum undulatum and Anthoceros levis among Musciner. They are always present in growing points. In the lower Alge there is uniformly in the earlier cells a single large chromatophore in each cell, while the more highly differentiated later cells contain a large number of small chromatophores. The same is the case upwards to the simplest Muscineex, e. g. Anthoceros. The simplest Floridew—the Bangiacez and the true Nemalies—have a single chromatophore in each cell. In almost all plants the chromatophores change their form as the plant developes. In the lower plants, the simpler Chlorophycee and the Diatomex, the formation of leucoplasts is a subsequent process, a transformation of the coloured into a colourless chromatophore, while in the higher plants it is usually the reverse transformation that takes place. The Characeze are the lowest plants in which the leucoplasts have an important physiological function; in the Muscinee they play but little part; in the Pteridophyta and Phanerogamia they are much more important. The same is the case with the chromoplasts, which occur but rarely in the Chlorophycee. The chromoplasts are always formed at the expense of chloroplasts or leucoplasts. For the chromoplasts of the Pheophycexe the author proposes the term phzoplasts ; for those of the Floridex rhodoplasts. With the exception of the Anthocerotes, where there is usually a single large chromatophore in each cell, those of the Muscinez are very small and numerous, disc-shaped or polygonal. The chromato- phores of the Pteridophyta do not differ essentially from those of flowering phants. Leucoplasts are found in all those parts of Phanero- gams which are completely excluded from light ; in many of the parts exposed to light which perform other functions than those of assimi- lation ; and in some saprophytes and parasites. The simplest chromatophores consist of a colourless protoplasmic substance without any visible internal structure or contents; and this is sometimes the case during the whole of their existence, as with most leucoplasts. But usually the protoplasmic structure or stroma produces—mostly in its interior, less often on its surface—structures of various kinds. The chemical nature of the stroma is very little known; the protoplasm of the chromatophores has been termed by Strasburger chromatoplasm. * Pringsheim’s Jahrb. f. Wiss. Bot., xvi. (1885) pp. 1-247 (5 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 641 The leucoplasts are usually globular quite colourless structures, often considerably more refringent than the surrounding protoplasm. In a number of Angiosperms the chromatophores contain protein- crystals, which are isodiametric, tabular, or prismatic. The chroma- tophores of many Alge, and those of Anthoceros, contain pyrenoids, one or more buried in the matrix of the chromatophore, like nucleoli in the nucleus. Except in Porphyridium cruentum (Palmella cruenta) they are always colourless, and of a more or less delicate reticulate structure. They are segments of the chromatophores in which a peculiar nuclein-like substance is imbedded; they may increase by division or by new-formation. Jn many flowers and fruits the chromoplasts have a crystalline appearance, from containing crystalline substances which are either albuminoids or pigments; or both may occur in the same chromoplast. The two kinds are distinguished by their different colour, their dif- ferent behaviour to reagents, difference in form and in the degree of double refraction, and by the pigment-crystals being always strongly pleochroitic (not dichroitic). But in most cases the pigment of the chromoplasts is not crystalline; it does not then permeate the protoplasm-strings, but is contained in small vacuoles in a fluid or semi-fluid, or sometimes a solid condition. The chromoplasts are always formed by the transformation of other chromoplasts, either leucoplasts or more often chloroplasts. Chloroplasts have probably the same structure as chromoplasts ; they consist of a colourless stroma with numerous vacuoles filled by a green semi-fluid substance, The chloroplasts of all Pteridophyta and Phanerogamia contain granules, termed by Strasburger chromato- somes ; these are especially well marked in the prothallia of ferns. The same is the case with all the higher Muscineew; while in Anthoceros and in all Algee the chloroplasts are of a homogeneous green colour, or only very finely punctated, but not granular. In many green Alge the pigment is not uniformly distributed, but is chiefly accumulated in the marginal parts of the chromatophores. Tt has long been known that in some cases—the cotyledons of Conifers and the fronds of ferns—chlorophyll may be formed quite independently of light ; the author believes that this is generally the case with Muscinex, Characer, and Alge, and partially also with the Pteridophyta. The chlorophyll-pigment is destroyed by intense light. ‘ The chromatophores of flowering plants contain oil; and this occurs in all organs, especially in persistent leaves. The various substances produced from the chromatophores are never products of the cell-protoplasm or nucleus ; and the chemical changes which take place in the chromatoplasm are also different from those in the cytoplasm and nucleoplasm. The chlorophyll and starch are produced entirely by the chromatophores. The chromatophores are invariably enclosed in at least a thin coating of protoplasm. The arrangement of the chromatophores in the cell is sometimes altogether irregular; more often it is constant and in definite relationship to the cell-contents. In eells which do Ser. 2.—Vot. VI. IA T65 642 SUMMARY OF OURRENT RESEARCHES RELATING TO not assimilate it is probably the nucleus that supplies the material which is subsequently transformed into starch, . either from the chromatophores or from the cytoplasm. The chlorophyll-grains may either lie on the cell-walls bounding intercellular spaces—epistrophe, or on those bounding other cells—apostrophe. Light may cause movement of the chlorophyll-grains in two ways:—either dependent on the structure of the organism, and without reference to the direction of impact of the light —phototonic, or resulting entirely from the direction of the rays of light—phototactic. The apostro- phic or epistrophic arrangement is the result of complicated laws dependent on the action of light; very strong irritation of light causes the chlorophyll-grains to collect into one or two lumps, a phenomenon for which Schimper proposes the term systrophe. The result of a number of observations on this subject leads the author to the conclusion that light causes two quite distinct kinds of movement in the chlorophyll-grains; on the one hand the grains tend to move towards certain definite parts of the cell, varying according to the intensity of the light:—phototonic movements; on the other hand to place their broad surfaces parallel or vertical to the direction of the rays of light :—phototactic movements. The photo- tonic movements are identical with those caused by a decrease in the intensity of the light, by cold, and other sources of irritation; this identity depending on a specific energy of irritation. Movements of the phototactic description are, on the other hand, not produced by any other factor except light. Formation of Starch-grains in leaves from Sugar, Mannite, and Glycerin.*—-Herr A. Meyer shows that the leaves are able to form and to store up starch, not only from glucoses and cane-sugar, but also from mannite and glycerin. He concludes that the starch formed in leaves is the last member of a long series of compounds which are successively produced in the assimilating cells out of the carbon of the carbon dioxide of the air and other elements. The intermediate stages are very different in different plants. By applying Sachs’s test for starch to Béhm’s method of using sugar-solutions, the author shows that there are leaves which produce starch out of dextrose as well as out of levulose and galactose, if laid for a considerable period in the dark on solutions of these carbo- hydrates. Other leaves, again, will obtain starch out of only one or two of these carbohydrates ; and the plants in the cells of which any one of these kinds of sugar is found are especially capable of obtaining starch out of this particular kind. No plant was found able to form starch out of inosite. From cane-sugar all the leaves examined were able to form starch, also from maltose; but none from milk-sugar or melitose. From mannite the leaves of all species of Oleaceze examined which contain this substance were able to produce starch, while negative results were obtained with the leaves of other plants which do not * Bot. Ztg., xliv. (1886) pp. 81-88, 105-13, 129-387, 145-51. Cf. this Journal, ante, p. 101. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 643 contain mannite. Leaves of Huonymus europxus produced starch from dulcite, but not from erythrite. Leaves of Cacalia suaveolens obtained it readily and in abundance from glycerin. Experiments with triohymethyls, aldehyd, and organic acids, yielded negative results. Formation of Starch out of Glycerin.*—In connection with the experiments of A. Meyer } on the formation of starch, M. E. Laurent has proved the formation of starch in completely etiolated potato- shoots out of glycerin, as well as out of saccharose and glucose; negative results were obtained with acetic acid, oxalie acid, tartaric acid, dextrin, and tannin. With a 10 per cent. solution of saccharose, growth continued more than five months, and tubers containing starch were formed in the axils of the leaves; with a 5 per cent. solution of glycerin starch-grains were formed in the parenchyma of the stem up to a considerable height. Function of Tannin.t{— Dr. M. Westermaier maintains that tannin in the cells of plants is not a mere waste product of excretion, but possesses assimilating functions, connected especially with the forma- tion of albuminoids. By the action for several days of potassium bichromate, he determined its presence in the palisade-cells of the leaves of a number of plants, also in the conducting tissues, such as tho parenchymatous sheath which surrounds the conducting bundles, the conducting cells of the assimilating tissue, and in many elements of the xylem and phloem. Both microchemical reactions and analyses show that the autumnal fall of leaves is preceded by a more or less considerable diminution of the amount of tannin in the palisade-cells. If branches are ringed, the leaves above the ring contain more tannin at the end of September than the normal leaves in August. In its appearance and translocation, tannin shows analogies with starch. Nectar.s—Dr. A. v. Planta finds that the nectar of Protea mellifera, evaporated to a syrup, and thus obtained in large quantities from abroad, contains no nitrogenous matter, but 73°17 per cent. of solids, of which 70°08 is grape-sugar, and 1:31 cane-sugar. Grape-sugar was obtained from the syrup in a crystalline form. Besides the sugar, a small amount of formic acid (apparently brought by the bees) and ash was present. The following table gives the percentage of sugar in the fresh nectar of three plants examined :— Total Total Cane Grape Solids. Sugar. Sugar. Sugar. Nectar from Bignonia radicans .. 15°30 15°27 0°48 14°84 Protea mellifera .. 17°66 17°06 0:00 17-06 Hoya carnosa . 40°77 40°64 35°65 4:99 ” ” »” ” Aqueous extracts of various flowers were also analysed ; the small quantity of sugar present in them may be seen from the author’s calculation, that in order to obtain 1 gram of sugar (corresponding Bot. Ztg. xliy. (1886) pp. 151-2. T Cf. supra, p. 642. SB. K. Preuss. Akad. Wiss. Berlin, xlix. (1885) pp. 1115-26 (1 pl.). Zeitschr. f. Physiol. Chem., x. (1886) pp, 227-47. yan * + = S 644 SUMMARY OF CURRENT RESEARCHES RELATING TO with 1:3 gram of honey), the bees must suck 2129 flowers of the alpine rose, 2000 of the acacia (Robinia viscosa), and 5000 of the sainfoin (Onobrychis sativa). Proteid Substance in Latex.*—The examination of seeds of various plants has shown that certain globulins, albumose, albu- minates, and coagulated proteids, can be isolated; and Martin has investigated the nature of certain proteids in the dried milk of the fruit of the papaw plant (Carica papaya). Mr. J. R. Green now gives the results of his researches on several caoutchouc-yielding plants, and describes the numerous tests which he applied to the latex, preserved in alcohol. These researches were made on Mimusops globosa, Manihot Glaziovii, Brosimuwm galactodendron, and others; as well as on lettuce and cabbage plants. He agrees with Martin that no true peptone is present in plants. The following are the proteids found to be present :—(1) A dia- lysable proteid, resembling peptone, but which is not converted into true peptone by the action of pepsin. Martin’s proteid obtained from the papaw plant gives the biuret reaction, whereas this proteid does not do so, (2) Hemialbumose, found in the lettuce; this resembles Vines’s hemialbumose and Martin’s a-phytalbumose. (8) Albumose, in Mimusops. (4) Albumin, in Brosimum. (5) Globulin, in Manihot. Both the two last seem to be the same bodies as described by Martin as occurring in papaw juice. The albumin is probably the same substance as Boussingault’s “vegetable fibrin”; till lately no true albumin has been found in plants. New Nitrogenous Constituent of Plants.t—Herren HE. Schulze and E. Bosshard have found a new chemical substance in young clover-plants, the cotyledons of cucumber-seedlings, young lupins, probably in the pollen of Pinus sylvestris, and ergot, usually in very minute quantities, in the last case alone amounting to 0-1 per cent. Tt crystallizes with the composition C,;H..N,O,, and its discoverers have given it the name vernin. By heating with hydrochloric acid it yields guanin. Pith of Dicotyledons.t—Herr F. v. Mentovich describes the pith in a large number of dicotyledonous orders, which he classifies under two groups, climbing and non-climbing plants. The following are some of the more important observations :— The pith-cells of woody plants may be classed under two physio- logical groups, according as their cell-walls are lignified or remain unchanged. In those cases where all the cells are lignified the change usually commences in the first, less often in the second or in later years. Passive pith results from the cells losing their vitality after becoming lignified; their walls are then all of the same thickness. * Proc. Roy. Soc., xl. (1886) pp. 28-39. + Zeitschr. f. Physiol. Chemie, x. (1886) pp. 80-9. See Bot. Centralbl., xxvi. (1886) p. 100. { Mentovich, F. von, ‘Histology of Pith, with especial reference to Dicoty- ledons’ (Magyar), 37 pp. (1 pl.), Kolozsvar, 1885. Sce Bot. Centralbl., xxvi. (1886) p. 67. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 645 Heterogeneous pith is the result when some of the cells still remain active at a later period, performing the function of a reservoir of food- material. The walls of these cells are usually thicker and more pitted: they are mostly the peripheral cells. It is not unfrequently the case that while some of the pith-cells lignify, others still show the cellulose-reaction. It is then always the central part of the pith which remains unchanged, while the peri- pheral cells lignify early and often become very thick-walled. In other cases finally the pith-cells do not lignify at all, and then later changes sometimes occur, such as the disappearance of older cells and the appearance of new ones in their place. When special elements are found in the pith, such as laticiferous vessels, resin-passages, tannin-receptacles, calcium oxalate, &c., these almost invariably occur also in the cortex. It is very rare for the pith to remain entirely unchanged. The pith of climbing shows no important differences from that of non- climbing plants. Mechanical Sheaths of Secreting Vessels.*—Dr. M. Meebius has ‘investigated the anatomical details where intercellular secreting vessels are surrounded by thickened cells, in a number of examples, especially a large number of species of Pinus, the roots of Philodendron, the stem of the ivy, the ovary of different species of Bromeliaces, the leaf-stalk of Angiopteris, &e. The species of Pinus examined may be divided into three classes : —(1) Those in which the resin-passages are surrounded by scleren- chymatous bast-like cells ; (2) surrounded by thin-walled cells with some bast-like cells intermixed ; (3) surrounded by thin-walled cells only. In all the species of Philodendron examined, with one excep- tion, the epithelium of the secreting vessels in the adventitious roots is surrounded by sclerenchymatous cells, forming a partially open or an entirely closed sheath. Three different modifications of this sheath are described. The author believes the function of the sheath to be in all cases a purely mechanical one. Medullary Rays of Dicotyledons,j—Herr E. Zache has made a comparative examination of the medullary rays in thirteen different species of dicotyledonous trees and shrubs. He finds the number in a square mm. to vary, as a general rule, between thirty and sixty, a strong deviation occurring in one direction in Platanus orientalis with eight, and in the other direction in Prunus Padus and Castanea vesca with ninety. Normal Root-buds.{—By normal root-buds Dr. M. W. Beyerinck means such as are formed in some plants during normal growth, not as the result of wounds such as those formed in callus. In Populus alba and Geranium sanguineum the author observed root-buds inter- * Pringsheim’s Jahrb. f. Wiss. Bot., xvi. (1885) pp. 262-301 (1 pl.). + Zeitschr. f. Naturwiss., v. (1886) pp. 1-29. Cf. this Journal, v. (1885) p- 826. t Nederl. Kruidk. Arch., 1885, p. 162. See Bot. Centralbl., xxv. (1886) p- 296, 646 SUMMARY OF CURRENT RESEARCHES RELATING TO mediate between the normal and callus-buds, formed on normal roots from callus, but without any previous injury. In the former case they spring from the parenchyma of the secondary cortex around the origin of the lateral roots; in the latter case by the metamorphosis of dormant lateral roots which have remained within the secondary cortex. The same has been observed also in Solanum Dulcamara and Brassica oleracea when pulled up and replanted upside down. Apices of roots form leaf or flower-buds in Ophioglossum, Selaginella, Platy- cerium, Neottia nidus-avis, Catasetum, Anthurium, Dioscorea, Viola sylvestris, and Balsamina. In almost all plants which produce root-buds the mode of origin is accompanied by some morphological peculiarity ; only in the most nearly related species is it altogether or even nearly identical. Dr. Beyerinck classifies root-buds according to the tissue in which they are formed, viz. either immediately below the growing apex of the root, in the pericambium, or from the older parts; and in this case either by direct metamorphosis of a dormant rudiment of a root, or from that part of the primary cortex of a lateral root which still remains imprisoned in the cortex of the mother-root, or thirdly from the merismatic layers which lie beneath the secondary periderm after the primary cortex has been thrown off, or beneath the suberous layer which clothes the primary cortex. The author gives a number of illustrations of the varieties of these different primary groups. In most Podostemacee the branching appears to depend mainly on the formation of root-buds, corresponding in their position to the two xylem-bundles of the biradiate root; they are formed in the central part of the primary cortex quite independently of the central cylinder. Serial Buds.*—According to M. J. Velenovsky, serial buds occur normally in dicotyledons, while in monocotyledons he has observed only a single case. They occur as buds on all the permanent axes, frequently as branches in the inflorescence. In some plants (Lonicera, Sambucus) they are found in every leaf-axil; in others (Fagus, Carpinus) only on luxuriant shoots. In Raphanus Raphanistrum there are not unfrequently as many as five serial branches in the axil of the leaf, carrying the subtending leaf with the last shoot far from the main stem. The development of these buds can be followed out well in Robinia Pseudacacia ; the serial buds are subordinate to the first bud, but are formed in the same way, and originate from the same cell-tissue. The first axillary branch always dies in the following year, and then the first serial bud developes into a branch. The function of these serial buds is to form a reserve in case of the loss of the first bud; sometimes they develope into vegetative axes, sometimes into flowers. Anatomical Structure of Senega-root.|—Herr O. Linde describes in detail the structure of the root of Polygala Senega, which presents several peculiarities. 'The medullary rays are all in connection with * See Bot. Centralbl., xxvi. (1886) p. 10 (originel in Bohemian). } Flora, lxix. (1886) pp. 1-32 (1 pl.). : ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 647 one another in the centre. The secondary increase in thickness of the root is anomalous in several respects. The thin-walled parenchyma, whether it increases radially or tangentially, i. e. whether it forms medullary rays or wood-parenchyma, remains capable of growth in all directions, and therefore of forming new cambium. Details are also given of the structure of the root in other species of Polygala. Partition of the Axis.*—M. D. Clos applies this term to any mode of division of the stem or root, restricting the term “dichotomy” to its older signification, the elongation of two buds produced in the axil of two upper leaves. Partition of the root, or polyrhizy, may be of four different kinds:—({1) The fasciculate roots of monocotyledons and of some dicotyledons, where the main axis is more or less destroyed, or very feebly developed (Inula Conyza). (2) Partition of the main axis into two, three, or four equal or unequal branches (Scorzonera, Daucus, Rumex, Cucurbita Pepo and maxima). (8) Bipartition of adven- titious and especially of fleshy roots (Dioscorea Batatas). (A) , Arrangement of the secondary roots in small bundles along the main axis (Reseda, Fumaria.) This may occur also on cladodes of Opuntia kept some time in water. Partition of the axis generally may be classed under the three heads of Bipartition, Tripartition, and Multipartition or Polyclady. Bipartition may be equal or unequal, and either of these may be normal or abnormal. A large number of special cases are described, taken from a great variety of natural orders. Relation between the Bloom on Leaves and the Distribution of the Stomata.j—Mr. F. Darwin finds a connection between the relative number of stomata on the upper and under surface of leaves and the presence of “ bloom ” or the coating of wax which protects the stomata from the rain which would otherwise close them and render them useless. In those leaves which have no bloom on either surface there is a strong tendency towards the accumulation of stomata on the lower surface; in all those in which the bloom occurs on the upper surface only, there are also stomata on that surface; while of those which have bloom on the under surface only, 83 per cent. are entirely destitute of stomata on the upper surface. Double Flowers.t—Rev. W. Woolls remarks that few double flowers have as yet been found amongst the Australian plants in the wild state. He mentions the Epacrids as having an especial tendency to produce double flowers, e. g. Epacris purpurascens, E. microphylla, E. impressa, Sprengelia incarnata, Astroloma humifusum. Amongst other orders he has found the following plants: Ranunculus lappaceus, Eriostemon obovalis, Boronia pinnata, Wahlenbergia gracilis ; the last is remarkable as it so soon loses its stamens after flowering. Although * Mém. Acad. Sci. Toulouse, vii. (1885) pp. 222-56 (2 pls.). + Journ. Linn. Soc. Lond. (Bot.), xxii. (1886) pp. 99-116. { Proc. Linn. Soc. N. 8. Wales, x. (1885) pp. 455-8. 648 SUMMARY OF CURRENT RESEARCHES RELATING TO it is usually considered that “hybridization aided by cultivation ” is the chief cause of double flowers, yet it is evident that some other factor must be present, since all the above occur double in the wild state. The author deems it probable that insects play a very im- portant part in this matter. Superposed Stamens.*—Mr. T. Meehan brings forward argu- ments in favour of the view that when stamens occur opposite to the petals and attached to their base, the ordinary theory of the sup- pression of an intermediate whorl of stamens does not account for the phenomenon so well as the hypothesis that the stamen is not in this case a metamorphosed leaf, but is a modified axial bud at the base of the petal. This view is supported by a description of the structure of the organs in question in Mahernia verticillata, a plant belonging to the Biittneriacez. Composition of the Pollen of the Pine.j—Dr. A. v. Planta gives the following as the composition of the pollen of the pine :— Water, 7°66 per cent. ; N, 2°65; (N x 6°25, 16°56); non-nitrogenous matter, 72°48; ash, 3°30; hypoxanthin and guanin, 0:04; saccharose, 11°24; starch, 7°06; cuticule, 21:97. By cuticule is meant the chemically changed substance of the cell-wall which overlays various structures and is in direct contact with the air. It is estimated by digesting the pollen for three days in a 5 per cent. solution of potash in alcohol, which removes the oil, &c. The residue is then boiled with semi-normal hydrochloric acid for two hours, which removes the last traces of starch; other soluble matters are removed by ether, and nothing but cuticle remains. Composition of the Ash of the Pollen of Pinus sylvestris.{— MM. A. Famintzin and D.§S. Przybytek find, in the pollen of Pinus sylvestris, 6°79 per cent. water and 3°30 per cent. ash. The com- position of the ash is as follows :—K,O, 34°95 per cent.; N,O, 3°62; MgO, 6-99 ; CaO, 0°88; P.O,, 28°56; SO,, 14°83; Cl1,0-99; FeO, and AJl,O,, 5:30; Mn,0,, a trace. The proportion of nitrogen was 2-4 per cent. By treating the pollen with a1 per cent. solution of soda, and acidulating with hydrochloric acid, a small quantity of a precipitate was obtained corresponding in its reaction to nuclein. Heterocarpous Fruits.s—Dr. A. N. Lundstrém illustrates the phenomenon of heterocarpy in fruits, especially in different species of Calendula and Dimorphotheca belonging to the Composite. Three different forms may often be found in the same species, viz. :— (1) anemophilous fruits, slightly curved, and with the outer pericarp extended into a floating apparatus for carriage through the air; (2) bristle-fruits, without any wing, and with a number of stiff hairs * Proc. Acad. Nat. Sci. Philad., 1886. pp. 9-11 (1 fig.). + Landw. Versuchs-Stat., 1885, pp. 215-30. See Journ. Chem. Soc. Lond.— Abstr., 1. (1886) p. 91. Cf. this Journal, ante, p. 97. ¢ Bull. Acad. Imp. Sci. St. Pétersbourg, xxx. (1886) pp. 357-62. Cf. this Journal, ante, p. 97. § Naturv. Studentsalls. Upsala (Bot. Sekt.) Nov. 3, 1885. See Bot Centralbl., xxv. (1886) p. 319. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 649 on the dorsal side pointing downwards, adapted for carriage by adherence to the hair or wool of animals; (3) larva-like forms, without wings or bristles, but with the outer pericarp folded in a wavy manner, so as to resemble the larve of microlepidoptera. The 1st and 2nd pass into one another by intermediate forms; the 3rd is an illustration of true mimicry, for the promotion of dissemination by deceiving insectivorous birds; these fruits are usually found in the central part of the inflorescence. Testa of Leguminous Seeds.*—Mr. L. H. Pammei describes the structure of the testa of a number of leguminous seeds, including that of the Calabar-bean, Physostigma venenosum, and the remarkably hard testa of the Kentucky coffee-bean, Gymnocladus canadensis, in which, in addition to the five distinct layers found elsewhere, there is a sixth very strongly developed layer of sclerenchyma. Vegetable Metagenesis.j—A new and consistent system of nomenclature is proposed by Prof. W. R. M‘Nab for variously named organs and processes in plants. Instead of using “ oophore” to express the sexual form of a plant, he suggests gametophore ; and as this may be either male or female, androgametophore and gynogametophore serve to distinguish them. The sexual cells themselves are androgametes or gynogametes, instead of “zoosperms” and “egg-cells.” The union of these two by a process of “zygosis” will give rise to a zygote or “ovum.” The organ in which these sexual cells are formed are androgametangia and gynogametangia, instead of the typical “antheridium” and “arche- gonium.” In this way a more uniform set of words is used for similar stages in the asexual stages (spore, sporangium and sporophore): and in the sexual stages (gamete, gametangium and gametophore). Moreover, asexual stages are either spores developed in sporangia, or buds which are not so contained, e.g. conidia, gemme, and frag- ments of a plant; and for these latter the author proposes blastidules : whilst blastogenesis would be the process corresponding to sporogenesis. When metagenesis occurs, it is an alternation between gamogenesis and sporogenesis; whilst blastogenesis may occur either in the sporophore or in the gametophore stage. 8. Physiology. ¢ Fertilization by Pollen-tubes.§s—Mr. J. Kruttschnitt adduces fresh observations in support of his theory that the fertilization of ovules is effected without the agency of so-called pollen-tubes, the conducting tissue of the style serving to convey the fovilla from the pollen-grains to the entire inner surface of the ovary. * Bull. Torrey Bot. Club, xiii. (1886) pp. 17-24 (2 pls.). + Scientif. Proc. R. Dublin Soc., iv. (1885) pp. 451-4. ¢ This subdivision contains (1) Reproduction (including the formation of the Embryo and accompanying processes); (2) Germination ; (3) Nutrition; (4) Growth; eee) a (6) Movement ; and (7) Chemical processes (including Fermen- ation). § Proc. Amer, Soc. Mier, 8th Ann. Meeting, 1885, pp. 62-5 (1 pl.). 650 SUMMARY OF CURRENT RESEARCHES RELATING TO Endosperm of Dicotyledons.*—Prof. C. F. Hegelmaicr confirms the accepted view that the nuclei of the endosperm result in almost all cases from division of the secondary nucleus of the embryo-sac which has been formed by the coalescence of the two polar nuclei. Exceptions appear to occur uniformly in Hibiscus T'rrionwm, and probably in many cases in Adonis autumnalis, where this coalescence does not take place, but the endosperm is formed by repeated bipar- tition of the two free nuclei of the embryo-sac which remain distinct. The further development of the endosperm may vary according to four types, viz. :— 1. The omnilateral peripheral type. The nuclei formed by division from the secondary nucleus of the embryo-sac occupy the whole periphery of the embryo-sac; the first cells arise as a simple connected layer clothing the entire embryo-sac, and ultimately filling it up by centripetal divisions. This is the most common mode; examples are furnished by Adonis, Caltha, Cotoneaster, Malva, Hibiscus, &c. 2. The peripheral simultaneous type. The cells are formed simultaneously in the entire periphery of the embryo-sac; there is no later centripetal division of them; the comparatively narrow embryo- sac being filled up by the first formation:—Bocconia, Scabiosa, Euphorbia. 3. The unilateral peripheral type. Cell-formation takes place chiefly in the end of the embryo-sac nearest the micropyle; the tissue formed here afterwards extending towards the chalaza :— Trigonella, Phaseolus, Fagopyrum. 4, The endogenous type. The first cells of the endosperm are not formed in the periphery of the embryo-sac, but simultaneously throughout the whole protoplasm. In this type alone is the entire mass of the embryo-sac filled uniformly with nuclei before the forma- tion of the endosperm-cells :—Observed only in Hranthis hiemalis. The author observed in many cases both direct and indirect cell- division even in cases of normal development. Action of Saline Solutions on Germination.j|—According to experiments carried out by Herr Jarius, which are described in detail, no injurious effects on the germination of seeds can possibly result from the use of manures, as their solution in the soil can never exceed 0:4 per cent. Still the seed should not be sown immediately on the manure, as in such a case it is possible that a stronger solution may be formed. Ina table is given the ratio between the growth of the radicle and plumule of several seeds when subject during growth to different strengths of the same solution. Action of Hydrocyanic Acid on Seeds.{—Herr E. Schar cor- roborates Schénbein’s experiments on the action of hydrocyanic acid * Nova Acta K. Leop.-Carol. Deutsch. Akad. Naturforscher, xlix., 104 pp. See Bot. Centralbl., xxv. (1886) p. 302. + Landw. Versuchs-Stat., 1885, pp. 149-78. See Journ, Chem. Soc. Lond., Abstr., 1. (1886) p. 90. ¢ Journ. Chem. Soc. Lond.—Abstr., 1. (1886) p. 575, from Chem. Centr., cxxxi. (1885) p. 826. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 651 on the germination of seeds. He also finds that this acid arrests the germination, but on its removal germination takes place to an extent almost equal to what it would be if they had only been treated with pure water. He also adds that hydrogen sulphide and mercuric chloride arrest germination, but when the solution is very dilute (0:5 per 1000) 60 to 80 per cent. of the seeds still germinate. Formation of Amides during the germination of seeds in the dark.*—Herren B. Schulze and E. Fiechsig find that when the seeds of leguminous plants or cereals germinate in the dark, the con- version of albuminoids into asparagin and its congeners is very gradual; and that it also varies considerably, leguminous plants, and especially lupines, producing, not only absolutely but also relatively, larger quantities of amides than cereals do. Seeds, when germinating, do not of necessity produce an amount of amides at all proportional to their nitrogenous reserve-matter. Absorption of Light by the Assimilating Organs.j—Herr J. Reinke has made a series of photometric observations on the absorp- _ tion of light by the assimilating organs in a variety of plants, in- cluding a number of flowering plants, green, brown, and red seaweeds. For the colouring matter of the two latter classes, contained in the living active chromatophore, he proposes the terms phzophyll and rhodophyll respectively. The author suggests that the colourless albuminous constituent of the chromatophores acts like a ferment in enabling the chlorophyll to decompose the compound CO ;H, with evolution of oxygen when- ever the atoms of the albuminoid are set in motion by light with sufficiently large vibrations. When the body of the cell and the chromatophore die, the molecule of chlorophyll breaks up into its colourless and coloured group of atoms. The coloured constituent is soluble in alcohol, and either breaks up by dissolution into a green and a yellow constituent, or this separation exists previously. Phao- phyll and rhodophyil consist each in the same way of an albuminoid and a coloured constituent. In the former case the coloured con- stituent is very nearly related to the coloured group of atoms in the molecule of chlorophyll. In the coloured constituent of rhodophyll two groups of atoms can easily be distinguished, one of them agreeing, in its light-absorp- tion and solubility in alcohol, with the green constituent of chlorophyll, while the other absorbs most strongly the green rays which the chlorophyll allows to pass through most completely, and is insoluble in alcohol, but soluble in water. This group of atoms is characterized by an orange-red fluorescence on the death of the chromatophore. Development and Absorption of Heat by Plants.{—M. G. Bonnier finds that the quantities of heat developed in a unit of time by * Landw. Versuchs.-Stat., 1885, pp. 137-49. See Journ. Chem. Soc. Lond. —Abstr., 1. (1886) p. 90. + Bot. Ztg., xliv. (1886) pp. 161-71, 177-88, 193-200, 209-18, 225-32, 241-8 C1 pl.). ¢~ Comptes Rendus, cii. (1886) pp. 448-50. 652 SUMMARY OF CURRENT RESEARCHES RELATING TO the same weight of living tissues differ very considerably with the stage of development, and usually pass through successive maxima and minima. The most important maxima correspond with the commencement of germination and flowering respectively. These are also the stages at which respiration is most intense, but if the quantities of heat corresponding with the amount of carbonic anhydride evolved in a given time are compared with the heat actually developed during the same time, there is never any sensible agreement between the two quantities. The quantity of heat developed is not equal to that which would be produced by the combustion of the carbon lost by the organism. At the commencement of germination, the heat actually developed is much greater than that calculated from the amount of carbonic anhydride evolved, and even greater than that which would be developed by the combination of carbon with the whole of the oxygen absorbed during germination; but after germination, and during the formation and maturing of the fruit, the reverse is the case. These facts agree with the hypothesis that the reserve substances, which are not directly assimilable, are usually formed in the organism with absorption of heat; whilst the transformation of these substances into assimilable materials is accompanied, as a rule, by a development of heat. During the consumption of the reserve sub- stances, as at the commencement of germination, the heat developed by the transformation of these substances is added to that developed by the formation of carbonic anhydride ; but whilst reserve substances are being formed, as during the maturing of the fruit, the heat actually developed is the difference between that absorbed in the formation of the reserve material and that developed by the formaticn of carbonic anhydride. Movements of the Tendrils of Cucurbita.*—From observations of the movements of the tendrils of Cucurbita maxima and Pepo, Prof. D. P. Penhallow has come to the following general conclusions : —Growth is promoted by an increase of temperature and humidity, but may be retarded by an increase of temperature when other conditions are not favourable. The conditions favourable to growth, arising from temperature and humidity, may cause greater growth during the day, in opposition to the retarding influence of light. Growth is retarded by excessive transpiration. The conditions to which the plant is subject being variable, there is a corresponding periodicity in the vital phenomena. Movements of tendrils and terminal buds, being phenomena of growth, are modified by whatever variations of condition affect growth. The term vibrogen is given by Prof. Penhallow to certain areas of tissue in the tendrils immediately beneath the epidermis, composed of rather large and rounded parenchymatous cells with somewhat thin walls, and containing protoplasm and a large amount of chlorophyll, which appear to play an important part in the movements. With reference to circumnutation of the tendrils, movements of * Amer. Journ. Sci., xxxi. (1886) pp. 46-57, 100-14, 178-89 (i pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 6538 the tendril or petiole are due to unequal growth by producing unequal tension of tissues. The unequal growth is chiefly defined in the vibrogen tissue, which may therefore be regarded as the seat of movement. The band of unequal growth does not arise at successive points of the circumference. The vibrogen tissue consists of three longitudinal bands, each of which becomes more active in turn, without regular order. Bending under the influence of irrita- tion results from cessation of growth and condensation of structure. The collenchymatous tissue is that which is chiefly concerned in variations of tension under mechanical stimuli. Coiling results (by contact) from cessation of growth and condensation of structure or (free coiling) from increased inequality of tension due to continued growth. Transmission of impulses is effected through continuity of protoplasm in the active tissues. Ascent of Sap.*—M. L. Errera describes a series of experiments on this subject, made on the large vessels of Vitis vulpina. By in- jecting into the stem a solution of gelatin melting at 33° C., and coloured with Indian ink, he found that in all cases, when the -experiment was carried out with all possible precautions, the in- jected branch took up no water and faded in a few hours. This was considered conclusive evidence against the imbibition theory of Sachs, and in favour of the view that the ascending current of sap takes place through the cavities of the vessels and tracheides. Variation of Water in Trees and Shrubs.{—According to Prof. D. P. Penhallow, the hydration of woody plants is not constant for all seasons, but depends on conditions of growth. It reaches its maximum during the latter part of May or early in June, and its minimum during January. It is greatest in the sap-wood ; least in the heart-wood. The greatest hydration is directly correlated with most active growth of the plant, while lignification and the storage of starch and other products are correlated with diminishing hydration. The amount of water in dead wood varied, in 15 species of tree, between 12°9 and 19:0 per cent. In living wood, the maximum percentage observed was 61; it is usually somewhat less in the second year than in the first. Migration of Nitrates in Plant Tissues.t—-M. G. Capus’s method of study was the microchemical one. Sections of various plant tissues were immersed in a weak solution of Arnaud’s reagent, cinchonamine hydrochloride acidified with hydrochloric acid. After a longer or shorter period, according to the quantity of nitrates present, crystals of cinchonamine nitrate separate out ; the size, shape, and position of the crystals, whether within or without the cell, also afford indications of the relative abundance of nitrates in the different tissues. The author's observations demonstrate that many plants have the * OR. Soc. R. Bot. Belg., xxv. (1886) pp. 24-32. + Canadian Record of Science, ii. (1886) pp, 105-16. t~ Ann. Agronom., xii. (1886) pp. 24-42. Cf. Journ. Chem. Soc, Lond.— Abstr., 1. (886) pp. 484-5. 654 SUMMARY OF CURRENT RESEARCHES RELATING TO peculiar property of storing up an excess or reserve of nitrates especially in the medullary parenchyma of the stem and in the cortical parenchyma. This reserve is greatest at the period immediately preceding the flowering; the nitrates are then stored chiefly in the lower third of the stem, and are designed for the nutri- ment of the physiological summit of the plant, namely the flowering axis. If a branch containing nitrates in the stem, and showing a flowering axis, be cut off and plunged in distilled water, the nitrates soon disappear, and as they are not found in the water, must be con- sidered to have been used by the plant. Also, if a branch of this sort be cut off above the reserve of nitrates and plunged in a 0-004 solution of potassium nitrate, sections just below the flowers soon show the presence of nitrates. The power of accumulating nitrates is a specific property of certain plants. Among those particularly rich in this reserve of nitrates are Solanum tuberosum, Urtica dioica, Mercurialis annua, Sinapis alba, Brassica oleracea, Spinacia oleracea. Amongst those not containing nitrates in excess are Senecio vulgaris, Syringa vulgaris, Viola tricolor, Malva, Rumex, Phaseolus, and Chrysanthemum. Berthelot and André consider that the cells of the stem have the power of elaborating nitrates. Boussingault’s opinion, which is corroborated by the author's experi- ments, was that the nitrates enter the plant as such from without, and are assimilated in the plant. Branches of dahlia, selected when free from nitrates, and plunged into a solution of ammonium sulphate, have never shown the formation of nitrates in their tissues. The author suggests that exhausting crops are those which possess the special property of storing up nitrates. Action of Salicylic Acid on Ferments.*—Mr. A. B. Griffiths finds that a solution containing 0:2 gr. of salicylic acid per 1000 c.cm. of water destroys very quickly Mycoderma aceti, Bacterium lactis, and the butyric bacillus. It appears to act on and dissolve the cell-walls of these organisms, as also of dead Torule ; although living Torulz are not acted on, nevertheless their activity is impeded by the salicylic acid. Thus neither yeast nor saliva exert their fermenta- tive faculties in the presence of this solution of salicylic acid. The yeast can, however, be revivified by treatment with sodium phosphate and potassium nitrate. Hence “diseased yeast” may be advan- tageously treated with such a solution of salicylic acid which is far below the poisonous strength. Behaviour of Guanin, Xanthin, and Hypoxanthin in the Fermentation of Yeast.;—Meaning by hypoxanthin, hypoxanthin + adenin, Herr V. Lehmann finds that when yeast is allowed to stand in water at the ordinary temperature of a room, only small traces of these bases are set free from the nuclein; while if the temperature is that of the body, the entire quantity of hypoxanthin is smaller, that of guanin + xanthin larger. * Chem. News, liii. (1886) pp. 28-9. + Zeitschr. f. Physiol. Chemie, ix. (1885) pp. 563-5. Sce Bot. Centralbl., Xxvi. (1886) p. 101. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 655 B. CRYPTOGAMIA. Apospory in the Thallophyta.*—Prof. W. R. M‘Nab calls atten- tion to certain phenomena in the Peronosporeew and in Vaucheria which are to be regarded as cases of apospory, which occurs only under certain conditions. In Cystopus candidus the moniliform series of cells found below the epithelium of the host and usually called conidia, are to be considered rather as detachable sporangia, from comparison with other members of the group. In C. Portulacez the first and oldest sporangium of the series behaves differently from the remaining ones ; it does not liberate its contents, but developes directly into a new thallus; it is aposporous. Phytophthora infestans exhibits apospory when the sporangia are grown in moist air, hyphe being produced; whereas if placed in water zoospores are developed. Peronospora gangliiformis and P. parasitica also exhibit the phenomena. In Vaucheria tuberosa there is a complete series of gradations from the production of ciliated zoospores to spores which do not leave the sporangium, and to complete apospory. The author does not agree with Bower in regarding as apospory the artificial production of protonema from cut pieces of sporangium in certain mosses ; it rather approaches “ blastogenesis.” In Batrachospermum an apospory is apparently present, where the spores are suppressed, the ovum giving rise to a protonema. In the Saprolegniexe apogamy has been observed, and Prof. M‘Nab suggests that this is a case of “apandry,’ where the antheridium fuses with the oogonium. The same term would be applied to the pollen-tube. Cryptogamia Vascularia. Development of the Antheridium of Ferns.t—Mr. D. H. Campbell describes the development of the antheridium in Onoclea Struthiopteris and sensibilis. When the mother-cell of the antheridium is first cut off from the male prothallium, it contains a distinct central nucleus. The first wall formed within the antheridium is funnel-shaped, with the broad portion directed upward. The second wall is approximately hemi- spherical and parallel to the outer wall of the antheridium. Finally, a third wall is formed, resembling the first in form, and cutting off the covering-cell of the antheridium. The antheridium now consists of four cells, three parietal and one central; the two lower parietal cells are annular, the upper one flat; each contains a nucleus. The division of the central cell begins either before or immediately after the formation of the covering-cell. The first wall is nearly vertical, and is soon followed by a second vertical one at right angles. The * Scientif. Proc. R, Dublin. Soe., iv. (1885) pp. 466-9. + Bull. Torrey Bot. Club, xiii. (1886) pp. 49-52 (1 pl.). Of. this Journal, vy, (1886) p. 498 ; ante, p. 106. 656 SUMMARY OF CURRENT RESEARCHES RELATING TO ultimate number of cells in the antheridium varies a good deal even in the same species. Each of the cells formed from the central cells contains a nucleus, and the antherozoids are formed directly from the nuclei. The nucleus becomes indistinct, but does not actually disappear; as soon as it is again distinctly visible, it has increased in size and has become curved; not only these curved nuclei, but the sperm-cells themselves, increase so greatly in size that the parietal cells are almost obliterated. The antherozoids escape by the dissolution of the division-walls. They remain for a few moments after their escape enclosed in the remains of the wall of the mother-cell, but this is soon ruptured, and the antherozoid swims rapidly away, dragging after it the remains of the contents of the mother-cell as a very delicate vesicle. Muscines. Assimilating System of the Sporogonium of Mosses.*—Dr. G. Haberlandt points out that in most Bryinee the sporogonium has a more or less perfect assimilating system, situated generally in the innermost layer of the wall of the capsule, and the peripheral paren- chymatous layers of its neck, especially in the latter when well developed. Examples are furnished by Phascomitrium pyriforme, Funaria hygrometrica, Bryum argenteum, Webera elongata, Meesia longiseta, and Tayloria serrata. ‘The same function is performed by the apophysis of most species of Splachnum as long as it is still green. The assimilating tissue is a palisade- or spongy parenchyma, It is marked by the presence of stomata, which are absent where this tissue is wanting, as in the Sphagnaceea and Andreexacee. The amount of chlorophyll contained in this tissue is very considerable. Formation of Pits in Mosses.t—Herr K. G. Limpricht states, that in all the European Sphagnacez there are simple pits in the wood- cells and medullary cells of the stem and branches, and that they are especially abundant at the spot from which springs a tuft of branches; they are found also in the septa of the swollen cells at the base of the leaves. Septa with sieve-like thin spots, rudimentary sieve- plates, occur in the stem and branches of Sphagnum, in the transverse section of many species, as S. contortum and squarrosum, both in the spongy outer cortex and in the woody and medullary layers. ‘These thin spots are often ranged irregularly, in other cases in radial Lows. In the true mosses, simple pits are a widely spread phenomenon, not only in the axis, but also in the leaves; in the thin-walled cells of the conducting bundles they appear to be wanting. The author finds them in great abundance in the stem of Andreza, Dicranum, Grimmia, Racomitrium, Bryum, Philonotis, Breutelia, Webera, Mnium, Bartramia, Hypnum, &c. In the mid-rib of the leaves they are * Flora, lxix. (1886) pp. 45-7. + JB. Scliles. Gesell. Vaterl. Cultur, lxii. (1885) pp. 289-90. > ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 657 found especially in the longitudinal walls of the cells; in many species of Dicranum and Hypnum they occur also in the lamina. Paraphyses of Mosses.*—-Herr F. Kienitz-Gerloff confirms the hypothesis of Leitgeb t that the structure of the female receptacle in Corsinia is specially adapted for keeping the archegonia moist until impregnation by the antherozoids has taken place; and points out that in a large number of mosses the same function is performed by the paraphyses, especially in those dicecious species growing in very dry situations, in which the male and female tufts are often widely separated, such as Polystichum piliferum. 'This view is confirmed by the fact that paraphyses are often nearly or entirely wanting in those species which grow in water or in very moist situations, like Fonti- nalis and Sphagnum. Hair-like Filaments on Moss-stems.{—Mr. W. Archer draws attention to some reddish, arborescent filaments on the stem of Aula- comnion palustre, resembling an algal parasite, but which he finds to be outgrowths from the stem. They give off numerous branches, which become interlaced and involve the leaves of the moss. He suggests that this may be a “ kind of secondary Protonema,” which, if detached, might give rise to 2 new moss plant. New Genus of Mosses.§—Herr K. G. Limpricht classifies the cleistocarpous mosses of Germany under seven genera, viz.:—l. Nanomitrium (Hphemerum tenerum Bruch). 2. Ephemerum. 3. Ephemerella. 4. Physcomitrella. 5. Acaulon. 6. Phascum. 7. Mildeella n. gen., with the following characters : — Vegetative characters agreeing with those of Euphascum, monce- cious; the true male shoots often two or three placed behind one another on the same pseudaxis. Seta reddish yellow with central cord, usually shorter than the perigonc; foot somewhat swollen; vagina ovate. Capsule thick-walled, with distinct neck and persistent straight or oblique conical operculum; wall of two layers; cells of the exothecium thick-walled, with a few rows of smaller roundish hexagonal cells in the annular zone, but without the characters of annular cells ; cells of operculum elongated, ascending slightly to the left; stomata few, only in the neck-portion ; tissue of neck loose, with clearly defined axis; air-cavity without threads. Peristome distinctly developed, composed of sixteen filiform papillose yellow teeth, each of two layers; often only fragmentary in the upper part, laterally coalescent at the base. Calyptra cap-shaped. Its nearest affinity is with Barbula, Hepatice of the Amazon and Andes.||—In this magnificent work Dr. R. Spruce describes 577 species of Equatorial American Hepatice, * Bot. Ztg., xliv. (1886) pp. 248-51. + See this Journal, v. (1885) p. 1035. } Ann. and Mag. Nat. Hist., xvii. (1886) p. 163. § Rabenhorst’s ‘ Krypt.-Flora v. Deutschland,’ Bd. iv., Die Laubmonse v. K. G. Limpricht, Lief. 3, Leipzig, 1886 (2 figs). Cf. this Journal, ante, p. 108. : | Spruce, R., ‘Hepaticaee Amazonice et Andine,’ 588 pp. and 22 pls. London, 1884-5. See Journ. of Bot., xxiv. (1886) p. 122. Ser, 2.—Vou. VI. 2 xX 658 SUMMARY OF CURRENT RESEARCHES RELATING TO the majority new to science, and very nearly all collected by himself between 1849 and 1862. Of these species, 283 are Jubulew, 274 Jungermannies, and 22 Marchantice. They are arranged under 51 genera, of which 8 are new, viz. Myriocolea, Chetocolea, Arach- niopsis, Mytilopsis, Anomoclada, Clasmatocolea, Syzygiella, and Sym- phyomitra. Of Lejeunia he describes 234 species, which he distributes among 35 sections. Algee. Development of Tissue-systems in Alge.*—Herr N. Wille has examined the structure and development of eleven genera of Florides, which he divides into two groups :—those with a single apical cell, and those with an apical mass of cells with peripheral growth. The first of these groups are again divided into four, and the second into two types. 1. Delesseria-type. (Hydrolapathum sanguineum, Delesseria alata, D. sinuosa, Odonthalia dentata). Growth always takes place by a single apical cell. The transverse walls which separate the primary segments are at first straight, but afterwards become curved convexly below. The primary segments are divided by two vertical walls into a smaller middle, and two larger marginal cells. 2. Khodophyllis-type. (Rhodophyllis bifidus.) Here there is a three-edged apical cell, from which segments capable of division are separated alternately on the two sides. The thallus is afterwards divided by walls parallel to the surface, and cousists therefore of two outer layers which have endochrome only on their outer walls and form the assimilating system, and of one or more inner layers which constitute the conducting system. 3. Ceramium-type. (Péilota elegans, Bonnemaisonia asparagoides.) The apical growth in this group has already been fully described by others. 4, Lomentaria-type. (Lomentaria kaliformis.) 'The apical cell is conical, and divides in several directions, some parallel to the base, others nearly vertical to the surface, by which segments are separated laterally. These last cells again divide rapidly into an outer large and an inner small cell, the former further dividing into two. 5. Chondrus-type. (Phyllophora Brodixi, P. membranifolia, P. rubens, Chondrus crispus.) Growth in length takes place by dicho- tomously branched rows of cells, the outermost of which divide by anticlinal and periclinal walls. No conducting hyphe nor reserve- system. The cells in the interior part of the thallus are greatly elongated and united by pores, and form a conducting system. 6. Sarcophyllis-type. (Sarcophyllis edulis, Furcellaria fastigiata.) The mode of growth is the same as in the last type. Both conducting and reserve-hyphe occur. The assimilating system consists of dicho- tomously branched rows of cells, each of which is connected with one or each side by a pore. * SB. Bot. Sallsk. Stockholm, Sept. 23, 1885. See Bot. Centralbl., xxvi. (1886) p. 86. Cf. this Journal, v. (1885) pp. 684, 841; ante, p. 109. . ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 659 Lithoderma and Hildenbrandtia.*—Herr R. Wollny has found Lithoderma fluviatile for the first time in Germany, and describes the structure of the unilocular sporangia ; he also gives a fuller descrip- tion of the marine L. maculiforme. The frond of Hildenbrandtia rivularis he finds to be composed, not of a uniform mass of cells, as usually described, but of closely packed filaments quite distinct for their entire length. Laminariacee of Japan.t—Herren F. R. Kjellman and J. V. Petersen describe several new species of Laminaria, Ecklonia, and Alaria brought from Japan by the Vega expedition, of which L. angustata represents the highest type yet discovered, with strongly localized sori; also the new genus Ulopteryx—of which the only species has been hitherto known as Alaria pinnatifida Harv.— with the following diagnosis :—Radix fibrosa; stipes alatus, alis demum latis- simis, undulato-plicatis, soriferis; lamina cryptostomatibus praedita, costata, pinnatim ramosa; soris in alis stipitis dilatatis expansis, zoosporangia elongato-ellipsoidea vel subclaveformia inter parane- mata lineari-claveformia unicellularia dense stipata fovens, Vaucheria sessilis.|—M. E. Dewildeman describes a singular form of this species, parasitic on leaves in a spring, in which some of the filaments branch copiously at the extremity, the thick branches interweaving into a kind of ball. These filaments were always barren. Auxospores of Cocconema and Navicula.§—M. P. Petit describes the mode of formation of the auxospores of Cocconema Cistula and Navicula crassinervia. We regards it as a process of simple asexual reproduction, never accompanied by any fusion of two masses of protoplasm. It is simply a case of regeneration of the frustules due to protoplasmic activity. Hoops of Diatoms.||—Dr. J. D. Cox supports the view that the hoops of diatoms are formed all at once out of the living contents of the frustule, and not by accretions upon the edge. The most notice- able difference between the hoops of different species of diatoms is that some are hyaline, while others are elaborately figured and orna- mented with markings more or less resembling those of the valves. These latter are persistent, forming a permanent portion of the struc- ture of the diatom, of which Isthmia nervosa and Biddulphia pulchella are familiar examples. The hyaline hoop seems usually to belong to the free-swimming forms, and those closely parasitic species in which a single frustule alone remains sessile upon and closely adherent to a larger alga or other support. A favourable illustration is afforded by Aulacodiscus Kittoni. The normal form of this diatom is a convex dise with four short * Hedwigia, xxv. (1886) pp. 1-5 (1 pl.). + Kjellman, F. R., and Petersen, J. V., Vegaexped. vetensk. iakttag., iv. (1885) @ pls.). See Bot. Centralbl., xxv. (1886) p. 327. t Bull. Soc. Belge Mier., xii. (1886) pp- 66-8 (1 pl.). § Bull. Soe. Bot. France, XXxli. (1885), Session Extraordinaire, pp. xlviii.—li. (1 pl.). || Proc. Amer. Soc. Micr., 8th Ann, Meeting, 1885, pp. 33-7 (2 figs.). PAE a 660 SUMMARY OF CURRENT RESEARCHES RELATING TO but large processes, from which run to the centre conspicuous double lines of large areole, giving to the valve the well-known appearance of being marked with a cross, the ends of which end in the hollow side of the crescent-shaped processes. In the two valves these are not opposite each other, but alternate; and so long as two or more frustules remain in a temporary filament, they are interlocked by each process fitting into the hollow between those of the neighbouring valve. The hyaline hoops are divided by well-defined sutures into five, six, or more parallel bands or rings. The corrugated appear- ance of the hoop is an optical illusion, as is shown by the fact that the hoops slide over each other when the new frustules separate after the self-division of the parent. The most noticeable characteristic of these hoops is that the sutures are not continuous lines going quite round the shell; but at one place they curve sharply upward towards the valve, so that a tooth from the next outer division of the com- pound hoop cuts through its neighbour. These teeth alternate upon different sides of the shell; and if the hoop be divided upon the lines of these sutures, it will be found to be made up of a connected series of imperfect rings or bands with a projecting tooth upon the edge, and with the curved ends of the band separated by a space into which would fit a similar tooth upon the adjacent band of the hoop. The direction of the teeth has a fixed relation to the valve to which each hoop is attached, uniformly pointing towards it. When the fission of the parent diatom is complete, and the two new frustules slide apart, the hoops have ripened so that the sutures between the bands open at the slightest touch. The division of each band by the tooth of the neighbouring one allows it to spring open, and the frustule (or pair of frustules ready for separation) is thus freed from the hoops, which fall to pieces of themselves. This mechanism Dr. Cox believes to be designed to facilitate the escape of the new diatoms from the shell of the old one. Similar structures are found in other genera of the family. Division of Stephanodiscus Niagare.*—From observations of this diatom, Mr. C. M. Vorce confirms the conclusions of Dr. J. D. Cox TF with regard to the hoop. By examining continuous series of gatherings the entire process of division may be seen. The first change observed is the widening of the connecting zone or hoop. The box of the frustule becomes in consequence deeper, until it is often as deep as it is wide ; and at the same time the endochrome increases in quantity. About this time there is seen an extremely fine line of division crossing the centre of the frustule in the middle of the central mass of endochrome, almost invisible at first, but gradually becoming more distinct, and at first soft and flexible. Later it becomes doubly clear across the frustule, and begins to exhibit indications of the future spines of the new valves. The frustule has now become double, composed of two frustules, each of which has its outer valve thick and strong with long spines, and its inner new valve thin and fragile, * Proc. Amer. Soc. Micr., 8th Ann. Meeting, 1885, pp. 139-41 (4 figs.). + See preceding notice. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 661 with only rudimentary spines. The endochrome in each of the frustules is disposed as it was in the original frustule before division began. As growth goes on in the new valves they become thicker, and separate from each other further and further, being apparently pushed apart by the growth of the lengthening spines, until finally they are sometimes half as far apart as the width of the original frustule. The hoop of the parent frustule goes on widening to accommodate this growth, until, when the two new frustules are completely grown, they are ready to separate, and to repeat the process each for itself. One or both of the frustules now drops out of the hoop, and it is not uncommon to find the wide hoop with one frustule attached and one gone. The new valve is in this species clearly formed by the deposition of silex in or upon a membrane previously formed, and not by growth along an edge. Finer Structure of certain Diatoms.*—Messrs. E. M. Nelson and G.C. Karop find that on examining certain diatoms with the finest oil-immersion objectives, and under conditions of illumination such as are absolutely essential if the full aperture, and therefore resolving power, of these glasses is to be utilized, some details of structure are brought into view which are otherwise quite invisible, and, as far as they know, have not hitherto been correctly described or properly figured. 1. Coscinodiscus asteromphalos. This diatom, although consisting of a single siliceous membrane, has a double structure, viz. coarse and fine areolations, the latter within the former. The coarse areolations are for the most part circular in outline, and the intervening silex is thick. Inside these areolations is a most delicate perforated membrane, the outermost row of perforations being much larger than the rest. This membrane is so thin and fragile that it is often broken out, and when this is the case the coarse areolations appear to have a crenated edge. 2. Isthmia nervosa. This is similar in construction to the above, having a single membrane with a twofold structure, a fine perforated membrane inside coarse areolations. The coarse areolations in this diatom are very large, and the silex correspondingly thick. At the same time the inner membrane is excessively thin and delicate as in C. asteromphalos. The perforations are large and irregular in shape around the margin, but smaller and circular in the centre. A broken areolation is figured to show the fracture passing through the perforations. 3. Triceratium favus, This diatom is very similar to the preceding. The coarse areolations are hexagonal in form and very deep. At the bottom of these is a delicate perforated membrane, the perforations being circular and arranged for the most part in rows. A figure is given showing a fracture passing through the minute perforations, the resolution of which may be considered one of the most crucial tests for the Microscope of the present day. 4. Eupodiscus argus. This diatom differs from the above, inas- * Journ. Quek. Micr. Club., ii. (1886) pp. 269-71 (1 pl.). 662 SUMMARY OF CURRENT RESEARCHES RELATING TO much as it possesses two separate membranes, one containing the coarse and the other the fine areolations. The outer is a strong, coarsely-marked structure, the areolations being for the most part circular or oval in outline. The intervening silex is granulated on the exterior, and has a brownish colour by transmitted light. With reflected light, however, it appears white and sparkling, not unlike loaf-sugar. The interior membrane is very transparent and covered with minute perforations (only lately discovered, and which have been called tertiary markings). But in addition to these are what have long been known as the secondary markings, viz. white bright spots, which are arranged in rows radiating from the centre. These secondary markings must not, the authors consider, be regarded as perforations, as they have not found an instance of a fracture passing through them. Another figure shows the secondary and tertiary markings on the interior membrane, as seen through the coarse areolations of the exterior membrane. The best way of examining the secondary mark- ings is to use a 1/2 or 4/10 objective, with a lieberkiihn, the specimen mounted dry, with the concave side uppermost. The tertiary are more difficult to see, and will require a higher power. The fracture passing through the perforations in a valve of Pleuro- sigma angulatum is also shown. This diatom has but one membrane, and only one kind of perforations. To show this properly a lens must be very well corrected, and have its glasses very perfectly centered. Lichenes. Gonidia of Lichens.*— Dr. K. B. Forsell replies to Zukal’s strictures in his ‘Flechtenstudien’t on the author’s views on the nature of the connection between the algal and fungal elements in lichens, and defends his statement in his work on the Gloeolichens, ¢ that Zukal has in many cases assumed, without sufficient evidence, a genetic connection between alge and gonidia, and has hence been led to incorrect conclusions. Fungi. Symbiosis in the Vegetable Kingdom.§— Prof. R. Hartig confirms the account given by Frank,|| of the occurrence of mycorhiza (Rosellinia quercina) on the roots of the oak. He considers, however, Frank’s statement that many Cupuliferea depend entirely on the mycelium of fungi for their nourishment as too absolute. It is not unfrequently entirely wanting ; and, especially at the period when the trees are taking up the largest quantity of water and nutrient sub- stances, the newly formed apices of the roots are entirely free from the fungus, which attacks them only in autumn and winter. * Flora, lxix. (1886) pp. 49-64. + See this Journal, ante, p. 112. t Ibid., ante, p. 485. § SB. Bot. Verein Miinchen, Noy. 11, 1885, See Bot. Centralbl., xxv. (1886) p. 350. || See this Journal, v. (1885) p. 844. ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 663 Mycorhiza of the Beech.*—Dr. P. E. Miller confirms Frank’s ob- servations | with regard to the mycorhiza on the young roots of the beech. He finds it especially in dry sandy soil exposed to the sun, where there are few earthworms, and where the soil has in conse- quence become exceedingly compact and hard. In such situations the lower roots of the beech trees die off, and they are nourished entirely by a reticulation of smaller roots near the surface. The ground becomes covered with a layer of dead leaves which is converted into humus by the attacks of fungi, rhizopods, &c. The finer roots of the beeches gradually approach the surface, and at length penetrate this layer, and the fungus-mycelium with which they become invested acts as a saprophyte, and conveys to its host the soluble humates and other substances formed in the layer of decaying vegetable matter. Vitality of Spores of Parasitic Fungi.{—Dr. A. B. Griffiths has experimented in the following manner: A quantity of spores of Peronospora infestans (potato-disease) were taken from a crop of diseased potatoes. These spores were then placed in a porcelain mortar along with about 5 grms. of a mixture of calcium sulphate and ‘ ealcium carbonate, which were thoroughly mixed together. This mixture was then placed in a small oven always kept at a temperature of 35° C. (dry heat). After the spores had been dried up with these mineral substances (which principally constitute the dust found in the atmosphere) for two months, they had not lost their vitality, for in the space of three days after ‘‘sowing” they began to penetrate into the mesophyll of the leaves (of a potato plant) through the stomata. The leaves of Solanum tuberosum, along with dried two months’ old spores of Peronospora, were kept in a warm, moist atmo- sphere, such conditions being favourable for the development of these spores. On the fifth day after “sowing” there was a mycelium which had ramified through the tissue of the leaf, and there was also observed the production of conidia-bearing branches making their appearance through the stomata of the leaves. After six months of dry heat another portion of the dust was examined under the Microscope, mounted in water as before. The cellulose wall of the spores appeared rather shrivelled. Their vitality had not disappeared, for after seven days from “sowing” on the potato leaf there was a rapid development of hyphe, &c.; thus showing that even after the spores had been dried up for six months as dust, they were capable of germinating, and each organism leaving its life-history upon the host-plant. Again, after being in a dried state for ten months, it was found that the spores had lost their vitality. They did not germinate upon the leaves of Solanum, not after being in contact with the leaves in a@ warm and a damp atmosphere for a month or six weeks. Under the Microscope the spores were seen to be shrivelled up and their protoplasm dead. * Bot. Centralbl., xxvi. (1886) pp. 22-6 (5 figs.). + See this Journal, v. (1885) p. 844. t Chem. News, liii. (1886) pp. 255-7. 664 SUMMARY OF CURRENT RESEARCHES RELATING TO From this investigation it will be seen that the spores of Pero- nospora infestans may be dried up in an atmosphere and preserved as dust for the space of eight months without the loss of their vitality, and will germinate again when favourable circumstances are offered for their development. Formation of Lignin in Fungi.*—According to Dr. C. O. Harz, the statements hitherto made with respect to true lignification in Fungi rest on erroneous observation, Experiments on a large number of species with anilin-sulphate and with phloroglucin and hydro- chloric acid, failed to detect any lignin reaction. The hard cortical shell of Elaphomyces, on the contrary, with its projecting knobs and warts, is stained yellow by the former, bright red by the latter reagent, thus showing an instance of true lignification in a fungus. In addition to his previous detection of lignin in Hlaphomyces cervinus, Dr. C. O. Harz f now finds it in the sclerenchymatous fibres of the capillitium of several species of Bovista, as determined by phloroglucin and hydrochloric acid. The lignin of these fungi appears to be more readily soluble in potash and soda than that of the higher plants. In a large number of fungi examined no trace of it could be found. Fungi which cause decay in timber.t—Mr. P.H. Dudley finds that the fungus most destructive to railway sleepers, planks, and bridge- timbers made of yellow or Georgia pine (Pinus palustris) is Lentinus lepideus. The mycelium secretes fluids possessing acid reactions, which readily soften the thin-walled tracheides, causing their dissolu- tion, and producing abundance of crystals of oxalate or phosphate of lime, or sometimes carbonate. As soon as the tracheides are softened by the action of this fungus, larve perforate and consume them, leaving the harder thick-walled cells in the condition of a series of shells. Abundance of Schizomycetes were found in connection with it. Fungus-bulbils, §—Herr H. Zukal has observed the bulbils already described by Hidam || in five fungi, viz. Dendryphiwm bulbiferum n. sp., Helicosporangium coprophilum n. sp., Haplotrichum roseuwm Lk., Melanospora fimicola Hans., and a Peziza. From these bulbils only conidial forms are, as a rule, developed. In two cases, however, the bulbils were transformed into fructifieations, and Zukal therefore regards them morphologically as these organs in an undeveloped condition. In the fructification of some Ascomycetes the bulbil-forms may occur as a normal stage of development. The so-called sclerotia of Penicillium glaucum are probably modified bulbils. * SB. Bot. Verein. Miinchen,. May 13, 1885. See Bot. Centralbl., xxiii. (1885), p. 371. + SB. Bot. Verein Miinchen, Jan. 13, 1886. See Bot. Centralbl., xxv. (1886) p. 386. J Journ. N. York Mier. Soc., ii. (1886) pp. 36-7. § Verhandl. K. K. Zool.-Bot. Gesell. Wien, xxxvi. (1886) pp. 123-36 (1 pl.). || See this Journal, iv. (1884) p. 421. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 665 Octaviania lutea.*—Herr R. Hesse describes under this name a new fungus found on decaying becch leaves in Hesse. Spherosoma fragile.t—Under this name Herr R. Hesse describes a new underground species, and takes the opportunity of revising the position of the genus, which he places, with Tulasne, among the Discomycetes, near to Rhizina, and not, as proposed by Berkeley and Broome, among the Tuberacer. It is altogether destitute of perithecia. Uredinez of Illinois {—Dr. T. J. Burrill gives a complete list of the Uredinee hitherto found in Illinois. It includes 20 species of Uromyces, 48 of Puccinia, 5 of Phragmidium, 1 of Ravenelia, 1 of Gymnosporangium, 1 of Cronartium, 4 of Melampsora, 2 of Coleosporium, 1 of Uredo (isolated), 2 of Ceeoma (isolated), 41 of Afcidium (isolated), and 2 of Restelia (isolated). Protophyta. ‘ Mastigocoleus, a new genus of Sirosiphonacex. §—Under the name Mastigocoleus testarum Herr G. Lagerheim describes a new species and genus of Phycochromacez found attached to the shells of marine molluscs, the first-observed marine species of Sirosiphonacez. The diagnosis of the genus is—Trichomata vaginata, ramificatione vera irregulariter ramosa, cellulis vegetativis uniseriatis cylindricis composita. Rami biformes, partim cylindrici, partim flagelliformes. Heterocyste singule (rarissime bine) terminales vel laterales, nun- quam interealares. Multiplicatio hormogoniis et cellulis chroococ- coideis. Spore ignote. Contentus cellularum homogeneus. The filaments appear to secrete an acid which dissolves the lime of the shell. The genus seems to have the greatest affinity with Mastigo- cladus Cohn, found in thermal springs, but differs in its terminal or lateral heterocysts and uniseriate branches. Presence of Micro-organisms in the Living Tissue of Healthy Animals. || —Herr G. Hauser has subjected this question to fresh examination, with the following results:—In the living tissues and tissue-fluids of healthy animals he finds neither pathogenic nor any other description of bacteria. When all kinds of Schizomycetes are excluded from animal tissues preserved in oxygen, hydrogen, or carbonic acid, in water or a nutrient solution, but the access of atmospheric air permitted, they undergo a similar retrogressive metamorphosis to that of the tissues in the living body, which decay in consequence of simple nutritive disturbances without the action of * Pringsheim’s Jahrb, f. Wiss. Bot., xvi. (1885) pp. 255-61 (1 pl.). + Ibid., pp. 248-54 (1 pl.). ¢ Proc. Amer. Soc. Micr., 8th Ann. Meeting, 1885, pp. 93-102. § Notarisia, i. (1886) pp. 65-9 (1 pl.). | Arch. f. Exper. Pathologie u. Pharmakologie, xx. p. 160. See Natur- forscher, xix. (1886) p. 94. 666 SUMMARY OF CURRENT RESEARCHES RELATING TO the bacteria of necrosis. The products of decomposition which result from the destruction of tissue independent of any action of bacteria have no pathogenic properties. Tenacity of Life in Micrococci.*—MM. Perroncito and Airoldi experimented on Micrococcus ambratus, the cause of pneumonia in calves, and on the Pneumococcus of the horse, in order to ascertain the relative lengths of time for which they could be kept alive. On one glass plate was spread some pure culture of M. ambratus; and on a second plate a similar culture, to which was added some sterilized water. These were then placed in a water-bath, at a temperature of 35° C. Each day a small portion was taken from each culture and sown in a tube containing gelatin. So long as the Micrucocci remained alive, they grew and formed small characteristic spots. Micrococcus from the pure culture remained alive at the sixteenth day ; the other was dead on the thirteenth day. Pnewmococcus, treated with sterilized water, died very much sooner—on the tenth day. Heated to 50° C., in the dry state, both were dead at the end of an hour. The authors conclude that Micrococcus resembles the non-spore-forming bacteria more than does Pnewmococcus, so far as resistance to high temperatures is concerned. Behaviour of the Spores of the Schizomycetes to the Anilin-dyes.t —Herr H. Buchner had already pointed out that spores of Bacillus subtilis which did not take up any anilin-stain on simply drying on the cover-glass, did so energetically when killed by heating in the dry or moist way, or by treatment with pure concentrated sulphuric acid or strong potash-ley. The same phenomenon occurs also in the sporiferous distemper-filaments if these are dried on the cover-glass, then slowly passed through the flame, moistened for a few seconds with concentrated sulphuric acid, and finally washed with water and stained by gentian-violet. The filaments then have a distinctly septated appearance, the separate cells are either somewhat thick and slightly stained or of normal width and strongly tinged, the spores intensely so. The remarkable fact is then seen that the spores, which previously lay in the vegetative cells of the filament, are driven out of them by the action of the sulphuric acid, some of them lying free by the side of the cells, some still adhering to their side-walls, in the act, as it were, of escaping. Precisely the same appearance is seen in Bacillus subtilis, which the writer regards as a fresh confirmation of the morphological identity of these two forms. The author explains this behaviour of the spores of the Schizomy- cetes towards anilin-pigments, on the one hand by the well-known fact that living protoplasm does not take up any pigment, on the other hand by his experiments, which show that the power of germination of the spores is destroyed by the same degree of heat which brings about their staining. He does not, however, agree with the hypo- thesis of Koch that the strongly refringent substance of the spores is * Arch. Ital. Biol., vii. (1886) p. 341. + SB. Gesell. f. Morph. u. Physiol. Miinchen, 1885, 4 pp. (1 fig.). See Bot. Centralbl., xxvi. (1886) p. 55. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 667 oil, but considers it probable that it does not differ in chemical properties from the protoplasm of the vegetative cells. Cultivation of Bacteria and Cholera-bacillus.*—Dr. L. Curtis has repeated Koch’s experiments on the “ comma-bacillus,” and agrees generally with his conclusions that it is unlike any other form, that it is peculiar to cholera, and is the cause of the disease. Dr. Curtis states further that the disease is not contagious; it is only by the bacillus gaining access to the intestinal canal that the disease is caused. The bacillus does not grow in acids; consequently when digestion is active, the chances of taking cholera are small. It is only at the times when the stomach has ceased to act, as during attacks of indigestion from whatever cause, that cholera comes on. The bacillus grows freely in water and on damp surfaces. It forms no spores, and is not found in the blood; inoculation is therefore useless. The germ is easily killed, as by a 10 per cent. solution of carbolic acid in twenty-four hours, by corrosive sublimate in a few minutes, or by superheated steam in half an hour. Cold checks its growth, but does not kill it. New Bacterium.t—Under the name Bacterium tortuosum Herr H. Zukal describes a form found in a tank, the water of which was at first coloured quite green by Euglena, but which lost its colour after the appearance of the masses of bacteria. The rods possessed a cilium at each end, and combined into zooglea-colonies, which assumed a ribbon-like appearance as the rod passed into the filiform form; these ribbons were 14-20 » broad and rolled up like shavings. On the fourth day after the swarming condition a great part of the spiral bands had formed spores; but the germination of these was not observed. Several new species of Fungi and Myxomycetes are also described. Bacillus Malarie.{—The observation first made by Laveran some years ago as to the existence of an amceboid organism in the blood of persons suffering from malarial fevers, and which disappears under the influence of quinine, has comparatively recently been confirmed by Drs. E. Marchiafava and A. Celli.§ The parasite is an extremely minute ameeboid organism found free in the blood, or in the interior of the red corpuscles or attached to them. In a certain stage of its development it possesses from one to three or four flagella, and is endowed with active movements. This form is, however, but rarely encountered. In addition to the above-mentioned facts, the organism is frequently found to contain granules of black pigment, such as has been ofttimes noted in the blood of patients suffering from malaria. But little beyond these is known of the life-history of the parasite, although Drs. Marchiafava and Celli have produced malarial paroxysms in persons previously * Proc. Amer. Soc. Micr., 8th Ann. Meeting, 1885, pp. 142-50. + Verhandl. K. K. Zool.-Bot. Gesell. Wien, 1885, pp. 333-42. t Cf. Science, vii. (1886) pp. 297-9 (28 figs.). § Fortschr. d. Med., 1885, pp. 339 and 787. 668 SUMMARY OF CURRENT RESEARCHES RELATING TO free from the disease by injecting blood which has been found to contain the organism, into their veins, and subsequently verifying the result after the onset of the intermittent fever. The publication of the researches of Marchiafava and Celli has provoked a reply from Prof. C. Tommasi-Crudeli,* who is of opinion that they have mistaken for the cause of the alteration of the red corpuscles, the effect of another cause. No pathologist, he says, would fail to recognize in the alterations depicted by them a retro- gressive metamorphosis of the red corpuscles, and no zoologist would be able to recognize from these illustrations the progressive develop- ment of an animal parasite; while the breaking up which Prof. Golgi, who has more recently corroborated the existence of the plasmodiwm malariz, calls segmentation, is cited as being the best of proofs of a retrograde change. The illustrations of the plasmodium are, says Tommasi-Crudeli, identical with those given by Rollett to show the effect of an electric shock on the red corpuscle of a frog.t The objections to the granules are that they do not move, and that they have not been seen to develope into plasmodia. The extensive reasons offered against the plasmodium are that hitherto no general progressive infections have been found to be caused by animal parasites, but on the contrary by vegetable ones; and, once admit that malaria is due to a living organism, it follows that it must be vegetable in nature, for how could an animal existence survive through long periods of time, buried deep in the earth, developing into activity as experience has shown of malaria frequently by accident? And yet we know that this has happened over and over again, even with vegetable organisms of much higher development than the Schizomycetes. Prof. Tommasi-Crudeli finally confirms the opinion originally promulgated by him, that the malarial ferment is a Schizomycete such as was described by himself and Klebs in 1879. Pneumococcus of the Horse.{—M. E. Perroncito investigated the cause of “croupal pneumonia” in horses, and found in the diseased lung (not, however, gangrenous) by means of sections stained with 1 per cent. methyl-violet, large spherical or ovoid micrococci, sometimes solitary or in twos, threes, and in even larger groups; these were frequently surrounded by a gelatinous capsule which does not stain. These organisms are Bacterium pneumoniz crupose ; their diameter is about 1°5 p. He obtained cultures on gelatin, and inoculated rabbits, horses, &e., which sooner or later died from lung disease, and from the lung he obtained bacteria similar to those injected. From various experiments the author concludes that the pneumo- coccus of the horse differs from that of man, (1) in that it is patho- genic in rabbits and other animals ; (2) in that the methods used for * Atti R. Accad. Lincei, ii. (1886) pp. 223-7. + Hermann’s Physiologie, Bd. ii. Th. i. t Arch. Ital. Biol., vii. (1886) pp. 343-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 669 colouring the gelatinous capsule are (at present, at any rate) insuffi- cient in the case of the pneumococcus of the horse. Microbe of Rabies.—Mr. G. F. Dowdeswell considers that he has found the microbe which appears clearly to constitute the virus of this disease. It is a micrococcus, not very minute, and of the usual form. It stains, however, with some difficulty; and this accounts for its having hitherto escaped observation. In the cases of dogs which he has as yet examined, its principal seat is evidently the central canal of the spinal cord and medulla oblongata; thence it pervades the other tissues of the central nervous system, occurring (sometimes in vast masses) around the walls of the blood-vessels, and in some cases within the vessels amongst the red blood-corpuscles. He found it in the cortex of the hemispheres, but in very small numbers, and, so far, only in the perivascular and pericellular lymph spaces. In the cerebellum it was not found at all, nor in the salivary glands. It does not stain by hematoxylin, either with or without a mordant, as asserted by Prof. Fol. Neither does it occur within the nerve-fibres, as he states; and lastly, it is fully three times the dimensions which he gives. It docs not occur in the same situation, treated by the same methods, in normal animals. In the one case of a rabid dog, which Mr. Dowdeswell had examined to control his previous observations, the tissues were placed in alcohol so shortly after death as to preclude the possibility of the occurrence of septic organisms. In addition to which, all saprophytes, as far as yet observed, stain very readily with the usual anilin dyes, which this microbe does not. Rabies.*—Prof. H. Fol has, by means of a second culture of his microbe of rabies, succeeded in inducing madness in the animals under experiment. He has sent cerebral matter of a rat thus inocu- lated to Pasteur, who has confirmed the statement that madness is transmitted to animals inoculated with it. Latterly Fol has experi- mented on the dog, in which the symptoms are more characteristic. The microbe shows itself under a constant form. The best way of obtaining a culture is to grind down the cerebellum and salivary glands with carbonate and phosphate of potash, then to filter through a “ Chamberland bougie.” The most potent rabies virus is in the brain and spinal cord ; it is less so in the salivary glands, and in the blood is completely absent. The propagation, then, is not carried on by the blood, but is transferred by nerves and by lymphatic vessels. Huppe’s Methods for the Study of Bacteria.;,—Dr. F. Hiippe’s exhaustive work on this subject commences with a brief statement of the various classes of bacteria, followed by the principles on which sterilization depends, together with the various methods, in- cluding that of discontinuous or intermittent sterilization. The various forms of bacteria are next described, with the method of * Arch, Sci. Phys. et Nat., xv. (1886) pp. 414-5. + Hiippe, F., ‘Die Methoden der Bakterien-Forschung,’ 3rd ed., 244 pp., 40 figs. and 2 pls. (8vo, Wiesbaden, 1886.) 670 SUMMARY OF CURRENT RESEARCHES RELATING TO observation of unstained and stained bacteria. Considerable space is devoted to the methods of staining the bacillus of tuberculosis, and especially its spores. The method of treating sections of tissue for the purpose of showing bacteria, and the various culture methods and materials are given; and something is said of saprophytic and parasitic bacteria. The work is illustrated by good woodcuts and two litho- graphic plates. MICROSCOPY. a, Instruments, Accessories, &c.* Watson-Crossley Microscope.—This (fig. 113) is a combination of the Oblique Illumination Microscope of Messrs. Watson (see this Journal, Vol. I., 1881, p. 516) and the Swinging Tail-piece Microscope with illuminating prisms, of Mr. E. Crossley (ibid., p. 653). The peculiarity of the former instrument, it will be remembered, consisted in the body-tube being set laterally on the limb, the latter being made to incline with the stage, on a horizontal axis in a line with the object, the mirror remaining fixed. By this means, and by the power of rotating the whole instrument round the mirror, illumination in all altitudes and azimuths could be obtained, without moving the eye, the light from the mirror remaining constantly upon the object. The second instrument was provided with a hollow swinging tail- piece, enclosing three prisms, by which the light from the lamp passing into the hollow trunnion axis was projected down the arm and thence upon the mirror; thus no change of the Microscope on its horizoutal axis affected the illumination which remained constantly on the object. The speciality of the new form consists in the above two ideas being combined. It would be difficult to do this if the tail-piece were retained in its ordinary place, as the one form requires much solidity in the axis on which the limb inclines, while the other necessitates the axis being made hollow. The swinging tail-piece with the substage and mirror is therefore separated from the Micro- scope and attached to a pillar on the opposite side of the base. As in the first-mentioned form, the mirror (detached from the tail-piece) can be fixed to the base. The stage also inclines on its axis as well as the limb with the body-tube. Thus the observer has the choice of obtaining oblique light in one and the same instrument, either (1) by inclining the body-tube over the fixed mirror, or (2) by using the mirror on the swinging tail-piece. * This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Iuminating Apparatus; (4) Other Accessories ; (5) Photo-micrography ; (6) Manipulation ; (7) Microscopical Optics, Books, and Miscellaneous matters. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 671 Fic. 113. wae “s = wm! H —_ “trom a Ti = —— — a 1 ae Warson-Crosstey Microscope, 672 SUMMARY OF CURRENT RESEARCHES RELATING TO Bausch and Lomb Optical Co.’s Physician’s Microscope.—The special features of this instrument (fig. 114) are the fine adjustment (described in Vol. IT., 1882, p. 683), the cradle-joint for inclining, and the glass stage. The latter rests on a forked support and could be made to give in a different form one advantage of Mr. Nelson’s divided Fia. 114. stage, as with glass the position of the illuminating apparatus would be readily seen. The slide-carrier would, however, require to be altered, so as not to impede the view beneath the stage. There is a removable substage and diaphragm. The pillar and arm, in the original form, were marked so as to indicate the correct inclination of the body in the use of the camera lucida. ‘The mirror is attached to a swinging tail-piece. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 673 Beck’s Mineral Microscope.—This (fig. 115) was devised by the late Mr. R. Beck for rapidly looking over large pieces of rocks. The body-tubes and pillar of a binocular Microscope are attached to a flat horizontal bar which is passed through longitudinal apertures in two sie a | wt standards which rise from a large wooden base. The ends of the bar project sufficiently to allow of its being moved by the hands from side to side and from back to front, so that the Microscope can be passed over a large rock placed on the base. The latter is 11 in. x 10 in., and the bar is 6 in. above it. Deutgen’s Micrometer-Microscope.—This Microscope (fig. 116) was devised and constructed in 1845 by Herr H. Deutgen, of Groningen, for the physical laboratory of the University of that city. The peculiarities are (1) the application of the Turrill system of mechanical stage, which had only then been recently invented by Ser. 2.—Vou. VI. Za, 674. SUMMARY OF CURRENT KESEARCHES RELATING TO Mr, Turrill in England ; (2) the two screw stage-micrometers acting at right angles, so that measurements can be made in both directions, and (8) the variable diaphragm beneath the stage, consisting of two rectangular plates, cach having a large V-shaped aperture, and so Fic. 116. arranged that a pinion at the side causes them to move together but in opposite directions, thus varying the size of the square aperture of the diaphragm from the full opening (14 in.) to a minute hole. The fine adjustment is by a direct-acting screw behind the body- tube, raising or lowering a stud to which is attached the support of the body-tube. The stage has spring clips connected by a rod, to grip glass cells of special design. The question of duly balancing the instrument on its inclining ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 675 axis was wholly neglected in the design; and indeed the slender attachments of the body-tube with its focusing adjustment, the ponderous mechanical and micrometer stages, and the adjustable diaphragm on the long square bar indicate on the part of the maker a very imperfect estimate of the necessity of stability for the purpose he had in view. Giacomini’s Microscope with large Stage.-—Signor F. Koristka, of Milan, sends us fig. 117 as showing the modifications which he has introduced into this instrument since its original design.* The lateral “ wings” by which the width of the stage is increased age We to 40 em. (wide enough to take sections of the entire human brain) are in the form of hollow trays, while the fine adjustment is now effected by an arrangement at the nose-piece acting similarly to the old form * See this Journal, v. (1885) p. 516, 7 i ag 676 SUMMARY OF CURRENT RESEARCHES RELATING TO of correction collar of an objective. The nose-piece consists of two tubes, the inner one being pressed upwards by a spiral spring encircling it; it is provided with two pins which travel in slots in the outer tube; a screw collar on the latter works against the pins, and thus controls the motion upwards or downwards of the inner tube. Nachet’s Corneal Microscope.—M. Nachet sends us fig. 118, showing his form of Corneal Microscope, which, unlike that by Schieck described Vol. IV. (1884) p. 954, has binocular body-tubes. The body-tubes E E are attached to the standard F, which consists of three tubes sliding in one another and intended to be clamped to the table. The body-tubes can be inclined ona hinge joint. There is a coarse adjustment at G. The leather-covered pads C C form a rest for the forehead of the person under observation, and B for his chin. They can be adjusted to different lengths. The little ball H is used as an object to be followed by the eye of the patient, so as to present different parts of the cornea to observation. D is a bull’s-eye con- denser. The screws on the standard are for adjusting the two arms in any desired position and for clamping the sliding tubes of the standard at any given point of extension. The instrument is also adapted for examining aquaria, and surfaces of all kinds, the skin, &e. Use of the Microscope in the Mechanical Arts.*— Mr. G. M. Hopkins indicates the many uses which may be made of the Micro- scope in workshops, not only for making fine measurements and * Central-Ztg. f. Optik u. Mech., vi. (1885) pp. 270-2 (10 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 677 examining the quality of the work, but also in the selection of material and observing its behaviour under different conditions. Thus the causes of the great differences in the efficiency of tools used in metal-working may best be detected and studied by the Microscope. The efficiency of the tool must depend not only upon the quality of the steel, but also upon the way in which the edge has been given to it. A tool sharpened upon a coarse grindstone is in reality grooved and notched, while one that has been smoothly ground Fig. 119. Fie. 120. Fig. 121. and finished upon a hone-stone shows a straight sharp edge; these characters are well seen with the Microscope, and are also betrayed by the surface of material worked by the tool. A coarsely ground tool (fig. 119) produces the furrowed and ridged surface of fig. 122 ; Fic. 122. Fic. 123. Fic. 124. one that has been ground upon an emery wheel which does not run truly (fig. 120) works the surface shown in fig. 123, where the metal has been torn out and not cut by the tool, while fig. 124 represents the smoothly-cut surface worked by a well-finished tool (fig. 121). 678 SUMMARY OF CURRENT RESEARCHES RELATING TO Fig. 125 shows another purpose to which the Microscope can be applied in the workshop to obviate the difficulty often experienced in making accurate measurements with callipers. Bisa bar with a micrometer scale, fastened to the right limb of a pair of callipers, and @ is an index fastened to the left limb. The work having been calibrated in the usual manner, the posi- tion of the index upon the scale is accurately determined by means of the Microscope A which is also carried by the bar B; and it is clear that in this way a precision is secured which is quite unattainable by the ordinary methods of calibra- tion. Finally the Microscope can with advantage be used to criticize the efficiency of the emery wheel; for this there is no better criterion than an examination of the fine dust thrown off at the edge of the wheel. If the cement is not hard enough, the particles of emery are soon loosened and removed; if on the other hand there is too much hard Kia. 125. Hre. 126. UPPEUN Sera ty ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 679 cement, the emery will remain enclosed in it and the wheel will only do its full amount of work by the exertion of undue pressure. A careful examination of the dust especially with regard to the proportions of cement, emery, and iron or steel particles which it contains, will show without doubt whether the wheel is well made and is doing its work efficiently. Under the best conditions the grindings should consist mainly of iron or steel with few particles of emery and few spherules of molten metal; if there is much emery present, the wheel is wearing too rapidly; while the presence of much molten metal indicates that too much pressure is being exerted. Fig. 126 represents the dust from a good wheel; here there are only a few angular particles of emery, while the particles of metal are sharp and clean cut. Fig. 127 contains a large quantity of emery and only little cement, while the particles of metal are as in the previous case, and the wheel will wear out very quickly. Fig. 128 represents the dust of a wheel which contains too much cement. The great pressure necessary to make it cut was sufficient to fuse the particles of iron or steel. Attached to the Kénigliche Technische Hochschule at Charlotten- ‘burg, Berlin, is a department for the preparation of microscopic sections where metals are cut, polished, etched, and mounted for the Microscope. With the sections are also to be obtained diagrams in one or more colours drawn to the scale of 50; 1.* The Microscope in the Workshop.t—Prof. W. A. Rogers in a paper read before the Boston Meeting of Mechanical Engineers, refers as follows to the use of the Microscope in the workshop :— “‘In the ordinary operations of the workshop, the lathe and the planer are the primary tools, while the caliper, with the graduated scale, is the secondary tool. Let us take the most simple case. It is required to turn down a piece of metal to a given diameter. In order to make the assumed case as simple as possible, we will assume the required diameter to be an even inch. The caliper is set for this unit of length, either from a graduated scale or, more accurately, from an end-measure inch with parallel faces. The setting in the latter case is done by the sense of feeling. We thus introduce an additional element of complexity, since sight is at once the primary sense and the ultimate test of a given limit of extension upon which the workman must rely. When the market is supplied with gradu- ated scales from which any required length may be taken by the sense of feeling, it will be in order to defend the practice of relying upon this sense as a final test in measurements of extension. As a differential test, it is both useful and accurate. As an absolute test it had better be abandoned. It is a makeshift at best. Assuming that the caliper has been set to an exact inch, the workman turns the piece of metal to the required size by a series of approximations with the ever-present risk of going beyond the required limit. During the final part of the operation he stops the lathe to test the * Central-Ztg. f. Optik u. Mech., vii. (1886) p. 131. + Cf. Engl. Mech., xl. (1886) pp. 397-8. 680 SUMMARY OF CURRENT RESEARCHES RELATING TO diameter with his caliper. He then takes another chip, stops, tries, starts, stops, tries, until the subtle and ever-varying sense of feeling satisfies him that he has obtained the correct diameter. But, after all, the uncertainty in the setting of the caliper remains, and this uncertainty is generally greater than that which would be found to exist in the comparative trials of the diameter, If, now, we increase the required unit, and especially if fractional increments are added, the problem of transferring a required length from a scale to a caliper becomes a most serious one. “Only one other objection remains to be overcome. It is the common impression that the delicate adjustments of the Microscope which are continually demanded—especially the adjustment for focus —can only be made by the most delicate and sensitive means. No impression could be more erroneous. Give me a small lead bammer and I will set the top of my comparator to a given line in half of the time and with greater precision than it can be set by means of a screw movement. Give me a vertical movement by means of an eccentric disc and a long lever arm, and I will bring the surface of a plate weighing 100 lbs. into the focus of the objective quite as quickly and quite as accurately as a similar adjustment could be made in the hands of a professional microscopist.” Klonne and Miller’s Diaphragm. — Herren J. Klénne and G. Miiller have patented* an ingenious diaphragm shown in figs. 129-133. It consists of two plates, each pierced with an aperture as shown in figs. 132 and 133. They are connected to a T-piece g by pins passing Fic. 129. Fig. 130. Fig. 131. Sp EE Se SS eee ee Se er Ca y = through the slots in the ends of the arms. This T-piece is attached to a frame sliding below the condenser, and just wide enough to allow of the plates moving backwards and forwards in grooves as the T-piece, turning on a central pin, assumes the different positions shown in figs. 129-131. In the first position the light is shut off, while in * German Patent, K1. 42, No. 34870, 26th August, 1885, 1 p. and 11 figs. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 681 the last we have the full aperture. Any intermediate degree of illumination can be obtained; the illumination is made excentric by shifting the whole apparatus laterally. An analogous device was constructed by Dollond, and is described and figured by Harting from a Microscope at Utrecht.* A practi- cally identical form which we recently obtained in England, is shown in fig. 134, where two plates with V-shaped apertures are made to Fic. 132. Fic. 133. Fig. 134. mT MT i TMU | | | [ies es) move simultaneously in opposite directions by racks and a pinion. The aperture can thus be varied from a pin-hole to half an inch. Deutgen’s Micrometer-Microscope (supra, p. 673) has the same form of diaphragm, which is however a fixture beneath the stage. Now that the Iris diaphragm, however, in the form used by Messrs. Beck in their “ Star” Microscope, can be made so cheaply, it would appear to supersede any of the forms of diaphragm above noted. Lieberkiihn Stops.t—Dr. G. W. M. Giles writes that during the process of examination and delineation it will be often found desirable to substitute direct for transmitted illumination, and to effect this change expeditiously he finds no appliance so useful as the old- fashioned but much-neglected Lieberkihn. To stop out the central rays of light he employs small discs of vulcanite, sawn out of a very thin piece of sheeting. By simply wetting them, these can be made to adhere to any part of the under surface of the slide, and can be shifted about if necessary with the tip of the finger, without removing the slide from the stage. By alternately employing direct and trans- mitted light, many details of structure can be learnt which could not possibly be made out by either alone, and it enables one also to fill in the natural colours in the finished drawing, which are quite lost by transmitted light. Ross’s Centering Glass—This apparatus was designed by Mr. A. Ross for ascertaining whether stage diaphragms, illuminators, and other appliances are properly adjusted in the optic axis of the Micro- scope, and acts on the principle that when suitable lenses are inserted in the body, or superadded to the eye-piece at various positions, they * Das Mikroskop, 1859, pp. 841-2 (2 figs.). + Sci.-Gossip, 1886, p. 121. 682 SUMMARY OF CURRENT RESEARCHES RELATING TO will give an extended conjugate focus to the object-glass, so as to convert the combination into a kind of telescope. The apparatus (figs. 185 and 136) consists of a pair of plano- convex lenses mounted in a tube fitting in an adapter which is placed Fig. 135. Fig. 136. over the eye-lens of an ordinary eye-piece when the eye-guard is removed. A pin-hole diaphragm is fitted over the upper lens, and the combined focus of the two is about Sin. To allow of adjustment for focus the lenses slide in the adapter, and when adjusted the eye- point (or “Ramsden” circle) can be focused and viewed through them. The centering glass is used in conjunction with a cap, having a pin-hole aperture, fitting over the illuminator, so that the collimation of the two pin-hole diaphragms with the source of light will afford a ready method of adjusting the illumination exactly in the optic axis. In practice, the pin-hole cap is first applied over the illuminator, and the image of the source of light seen through it is centered approximately with the ordinary eye-piece ; the centering glass is then put over the eye-piece, and the exact collimation is obtained by the adjustment of the centering-screws of the substage, and by slight movements of the mirror or source of light. Amici Polarizing Apparatus——We recently found in Florence a piece of apparatus belonging to an Amici Microscope, the construc- tion of which was somewhat puzzling. On submitting it to Mr. H. G. Madan, he reports as follows :-— “The apparatus (fig. 137) consists ofa square brass box containing 10 thin plates of glass (the glass has a decided blueish tinge, and is not very perfectly polished). On the top of the plates lies a right- angled prism of glass (refractive index = 1+512); the hypothenuse of the prism being parallel to, and in contact with, the top plate. The box is supported on a brass stem in such a position that the plane of the glass plates makes an angle of 118° (approximate) with the axis of the Microscope, under the stage of which it is fitted; and it ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 683 can be turned round on this stem in such a way as to preserve this angle constant for all azimuths. When it is placed so as to reflect light from the sky or a lamp up the body of a Microscope, this reflected light is found to be plane- polarized in the usual manner effected by reflection from a bundle of glass plates. Fic. 137. It seems clear that the instrument is in- A tended for use as a polarizing mirror, and | its action is of the following kind. | A .beam of ordinary light incident on a the prism at A emerges from the lower SS | aa face, when it falls on the latter at angles Soci a less than the critical angle 41° 24’, deviated A LAG (and, of course, also dispersed) to such an extent as to fall on the bundle of glass plates at the polarizing angle, 56°. It is thus polarized by reflection in the usual way, and passes upwards into the prism near the edge B. In its passage through - the prism its dispersion is entirely cor- rected, and it emerges as a colourless = plane-polarized beam in such a direction as to illuminate an object on the stage and enter the object-glass of the Microscope. The main advantage which the apparatus was intended to secure seems to be, to enable a ray to fall on the pile of plates at the polarizing angle without the necessity of placing the plates very obliquely to the axis of the Microscope. Thus there is a considerable gain in convenience and compactness.” Winkel’s Micrometer Eye-piece.—In such micrometer eye- pieces as that of Gundlach (fig. 138), where the micrometer m is LE a Fie. 138. SpA ll Simm inserted in a slit (covered by a ring r) and the eye-lens o is focused on the micrometer by moving it in or out, the magnifying power is altered with each change in the position of the eye-lens. 684 SUMMARY OF CURRENT RESEARCHES RELATING TO Herr R. Winkel * has endeavoured to remove this objection by leaving the eye-lens in a fixed position and moving the micrometer vertically by the contrivance shown in fig. 139. Here the micrometer m is raised or lowered by turning the cap a, which is connected with a piece g having a thread cut in it, and by this means e with the micrometer is raised or lowered in a similar manner to the arrange- ment for correction-adjustment in objectives. Herr R. Winkel overlooked the fact, however, that in getting rid of the objection to any movement of the eye-lens he had introduced a similar cause of error. Any movement of the micrometer shifts it from the plane of the image, and to bring the latter into coincidence again it is necessary to refocus the objective, and this alters the magnifying power. Method of Webbing the Filar Micrometer.t—Mr. D. Gill gives the following directions for webbing a micrometer. A spider (the variety is marked by a cross on the back, and is found in English gardens about decayed wood) is caught, and placed ona wire fork. The insect immediately attaches a web to the wire and begins to lower itself by the web to the ground. This web is wound up on the fork till ten or twelve turns, separated by a con- venient space, have been secured. A brush with varnish is then passed along the prongs; the webs are thus securely fixed to the fork. The parallel prongs of the fork must be sufficiently far apart to allow the web-frame of the micrometer to pass between them. The frame to be webbed is placed on a flat dull black surface between the prongs of the fork, the latter being carefully arranged so that one of the webs lies nearly in the furrow ruled in the frame for its recep- ticn. As the web-frame is generally thicker than the fork, the web will now be stretched across the former, with a certain amount of tension, and is brought into the furrow with a finely pointed piece of soft wood. Ifthe surface of the frame is well polished, and the furrows sharply cut without “ burr,” the web should leap sharply and decidedly into its place. Each end of the web is then secured by a drop of shellac varnish, which should be allowed to harden thoroughly before the frame is touched. The webs can be very readily so handled against a black background, with the aid of a hand lens of two or three inches focus. In experienced hands this method gives good results, but the following, which is generally followed on the Continent, is preferable. A web about two inches longer than the width of the frame, is unwound from a cocoon,t and small pieces of lead are attached to its extremities by beeswax. One end of the web, with its attached lead, is laid on a piece of cork floating ina tumbler of water; the other * Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 41-3 (2 figs.). Cf. Zeitschr. f Instrumentenk., v. (1885) p. 326. + Encyclopedia Britannica, 9th ed., xvi. (1883) p. 248. t It is asserted that webs from cocoons are more elastic, better shaped, and more durable than those obtained during an effort of the insect to escape. The best webs we have seen were from a cocoon obtained in Holland, but we have been unable to ascertain the name of the species of spider. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 685 end is allowed to hang down in the water, where it becomes thoroughly saturated and untwisted. It is then laid across the fork, and dropped into its furrows in the manner above described, the little lead weights exerting a definite tension. Varnish * is immediately applied to secure the webs, and the frame is not touched till it is dry. The bevel-edge of the web-frame introduced by Repsold offers great facilities for accurate webbing, and should, Mr. Gill says, be employed in all future micrometers. Schroder’s Differential-screw Fine Adjustment.—This device by Dr. H. Schréder was exhibited by Messrs. Ross in the Inventions Exhibition of 1885, and is shown in figs. 140 and 141. Fic. 140. Fig, 141. The nose-piece A is attached to a tube which is fitted to slide accurately in adjustable bearings in the body-tube B. The nose- piece tube has a short projecting arm C, by means of which it is pressed upwards by a strong spiral spring mounted in a cylindrical * Argelander used to apply two drops of varnish at each end of his webs. He first fixed each extremity by a drop of shellac varnish, and after that had dried he applied a drop of copal varnish nearer the centre of the frame; the latter took a long time to harden, but gave ultimately a much stronger attachment. 686 SUMMARY OF CURRENT RESEARCHES RELATING TO box L outside the lower end of the body-tube. The arm C is moved against the spring by the differential-screw mechanism (with milled head D) which is gimballed on a bracket E attached to the upper part of the body-tube. The differential-screw mechanism consists of a steel rod F (connected with the milled head D) which has two screw threads at the lower end, one working in a thread cut in the end of the inner tube G, and the other in the block H, which is soldered within the sheath J). When the milled head is turned to the left, the block, and with it the sheath, moves downwards while the rod itself, carry- ing the block and sheath, moves upwards. As the screws are cut respectively to 45 and 52 threads to the inch, the resultant motion is equivalent to the difference between the two screws, that is, to the motion of a screw of nearly 335 threads to the inch. The end of the sheath is tipped with asmall sphere K of polished steel, while the projecting arm of the nose-piece tube against which the end works has a corresponding concave bed of polished agate. Delicate Fine Adjustment.*—A delicate system of fine adjustment is described anonymously, but said to be “after Dr. Royston-Pigott.” It is skown in section and plan in fig. 142. The primary wheel carries an axis of steel, 1-3 inch thick, having an external thread exactly 1014 turns per inch, which travels Fic. 142. > me l) an 2X ZN in a brass nut having 60 turns ofa corresponding thread. This wheel has 100 teeth on the rim and engages a pinion of 10 teeth which forms one piece with the secondary wheel (removable at will), also divided into 100 parts. Each of the divisions on the secondary wheel represents a movement of the focal plane through a space of 1/230,000 in. There is also provision for changing the fulcrum so * Eng. Mech., xliii. (1886) p. 340 (2 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 687 as to make the advantage of the leverage 4 instead of 2-3 times; the finest wheel divisions then read 1/400,000 in. focal motion. The lever is very strong and rigid, and by a fork rests upon two studs diametrically placed on the sliding tube carrying the objective. The sliding tube bears upon extremely thin edges so as to make contact with as small surfaces as possible and thus minimize the friction. It should be highly polished and trued with crocus and paraffin, and when finished well supplied with chronometer oil. A further advance would be to have the pivot holes of the lever jewelled, drilled, and polished into a conoid form. Great care should be taken to thoroughly “ true ” spherically the free end of the fine screw. Several degrees of strength were tried of the depressing springs, acting as safety-guards on the objective touching “cover.” That finally selected (on reversing the instrument so that the objective was vertical and the wrong way up) gave a resistance of 4 oz. Less than this strength would be sufficient were the Microscope used perpendicularly. ‘On Fic. 143. the extreme accuracy of simultaneous contacts and pressures depends the steadiness of the -image under high powers, which should never dance in focusing ever so lightly, as it nearly always does in most Microscopes.” Mechanical Stages.*—Mr. A. Y. Moore “ con- demns such mechanical stages as have the milled heads above the stage. They are all well enough for amateur work—looking at mounted slides— but the room is not there, and the usual form of stage is to be preferred, even though the projection of the milled heads may be such as to prevent the complete rotation of the stage (and this is a very nice point—to talk about).” Ultzmann’s Saccharometer.—Dr. R. Ultz- mann has designed a cheap saccharometer to be used with any Microscope. The instrument (con- structed by Reichert, of Vienna) is a Mitscherlich saccharometer of small size ; it requires no special source of light, since when adapted to the Micro- scope it is sufficiently illuminated by the concave mirror. In fig. 148 a is the eye-piece and b the objective of a small Galilean telescope, of which the focus is at p; ¢ is the upper Nicol prism, to the mounting of which is fixed a vernier; d is the glass tube which holds the sugar solution, p is the plate of right- and left-handed quartz, and / is the lower Nicol. In using the instrument the body- tube is removed and replaced by the saccharometer ; the mirror is then adjusted so as to send the light up the tube. * The Microscope, vi. (1886) pp. 80-3, 688 SUMMARY OF CURRENT RESEARCHES RELATING TO The graduated circle of the upper Nicol is so divided that each division corresponds to the rotation produced by 1 per cent. of grape- sugar in the solution at a temperature of 20° Celsius; and by means of the vernier, readings are made to 0:1 per cent. In the case, there- fore, of raw sugar, the percentage must be taken as three-quarters of the number of divisions indicated on the seale, that being the ratio of the rotatory powers of raw and grape sugar. In all respects the instrument is used exactly as any saccharometer of similar construc- tion. ‘The advantages claimed for it are that it is cheap, requires no special stand or artificial light, Fia. 144. and gives the percentage of sugar in diabetic urine, &ec., directly by the vernier readings. Baker’s New Microscope Lamp.—This lamp (fig. 144) is a simplified and economical form of the one recommended * by Mr. E. M. Nelson for high-power work. Its chief advantages are that the flame can be used much nearer the table than in the ordinary Microscope lamps, while the dark-chamber metal chimney is arranged to receive a 3 X 1 in. slip, which can be of white, blue, or ground glass. Brass plates with various sized slots for regu- lating the amount of light can also be inserted in front of the glass slip. The metal chimney can be adapted to any ordinary paraffin lamp. Examination of Graduated Circles with two and four Micro- scopes.t—When the errors of a ST divided circle are to be determined i i microscopically for small ares round the whole circle, a very large number of observations is required. Dr. O. Schreiber investigates the general theory of the problem, and shows how it may be simplified in practice by a suitable selection and arrangement of the observa- tions. The divided circle is fixed and is centered on a disc which is free to rotate; the Microscopes can be moved independently of one another about the centre of the disc, so as to traverse the whole circle. Given a certain number of divisions on the circle and a certain number of Microscopes, the theoretically perfect method would make my) * See this Journal, iv. (1884) p. 125. i : + Zeitschr. f. Instrumentenk., vi. (1886) pp. 1-5, 47-55, 93-104. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 689 it necessary to fix the Microscopes successively in all possible posi- tions with regard to one another, for each position to set all the divisions in succession under one Microscope and make readings in all the others. “With four Microscopes and seventy-two arcs of 5° each, this would involve six million readings. Dr. Schreiber’s simplified method is as follows :—Fix the Micro- scopes at certain equal distances corresponding to certain arcs ; bring one division into the first Microscope A, and measure micrometrically the distance of the division seen in each of the Microscopes from its zero point. These readings form a “set.” A second set is got by turn- ing the dise until the next division comes into A; observe all the ares in this way, then all these sets form a “series.” Thus a series consists of as many sets as there are arcs, and a set of as many readings as there are Microscopes. It is impossible to abstract the details given by the author, for which reference must be made to the original paper. He finally gives “schemes” or arrangements of the observations for the following three cases; (1) Two Microscopes ; (2) four Microscopes which can be fixed in any positions; (3) four Microscopes fixed in pairs opposite #o one another; and compares the number of readings which they involve, from which it appears that method (2) is the most advantageous. Measuring the Focal Length of a Lens.*—Prof. E. Lommel adopts the following method:—At the point in the tube of an eye- piece O (fig. 145) generally occupied by the cross-wires, a semi-circular screen is fixed which obscures half the tube, the screen being divided Fic. 145. into two quarter-circles by a narrow vertical slit. Belind this isa mirror : or prism which sends light from an gjl_[2|,_ Ay | opening o in the side of the tube Le through the slit and into the lens L, which is so placed that its axis coincides with that of the eye-piece ; behind the lens is a plane mirror § which reflects the light back through it. The distance between lens and eye-piece is altered until the image of the slit appears sharply defined, and without parallax, as a prolongation of the slit itself. The distance between the lens and slit will then be the focal length, since the rays are in this case refracted through the lens as a parallel pencil, reflected back as parallel rays, and converge again to the principal focus at the position of the slit. This length is most conveniently measured by fixing the lens and the eye-piece upon stands which slide upon a graduated bar. Measuring Indices of Refraction.,—Prof. Lommel also de- scribes the following method :—The telescope F (fig. 146) of a spectro- meter, fixed and focused to an infinite distance, is provided with the eye-piece Oo described in the preceding note; the prism P whose * Zeitschr. f. Instrumentenk., vy. (1885) p. 124 (1 fig.). + Ibid., p. 125 (1 fig.). Ser. 2.—Vot. VI. 24 690 SUMMARY OF CURRENT RESEARCHES RELATING TO index is to be measured is adjusted in the usual way and fixed on the graduated disc T (with vernier at n and n), which is free to turn. The prism is first placed Fic. 146. with one face perpendicular to the telescope, so that the image of the slit reflected from the face is seen in the centre of the field. This is the initial position. As the prism is turned a spectrum appears in the upper half of the field ; each line of the spectrum, as it is made to coincide with the slit, represents a ray which has been refracted into the prism, reflected normally at the second face, and refracted out by the same path; hence the angle through which the prism has been turned is the angle of incidence 7 for that ray, while the angle of refraction is the angle of the prism. If the prism be turned further until the second face is perpendicular to the telescope, the difference of readings for the initial and final positions gives the latter angle, which is therefore the angle of refraction r for each ray. Then p = ——~ . The spectrum will reappear before the final position is reached at the point where the rays are refracted through the second, and reflected internally at the first surface; and the angle 7 is now the difference between the corresponding reading and that of the final position ; this gives a second determination of the index. This method dispenses entirely with the usual collimator ; it will be noticed, how- ever, that the angle of the prism must be less than the critical angle of its substance. This method is practically identical with that adopted by Prof. Abbe in his Refractometer, and Prof. Lommel subsequently acknow- ledged this,* not being aware of Prof. Abbe’s paper. Optical method for the absolute measurement of small lengths. —M. M. de Lépinay makes use of Talbot’s fringes, which are produced when a parallel-faced transparent plate is interposed in the path of a beam of light which has passed through a diffraction grating. If p is the index of the plate, ¢ its thickness, n the order of the fringe, = il then 2°"——t =n. The author measured by this means the thickness of a quartz plate cut parallel to the axis, and about 4 mm. thick, using the third spectrum produced by a grating of 400 lines to 1 mm. yp was taken as the mean of the best known measurements, A as the mean of the wave-lengths found by Mascart, Ditschreiner, and Van der Willigen. Rays of different wave-lengths give a succession of values for ¢, of which the mean is taken. The author claims greater accuracy for * Zeitschr. f. Instrumentenk., v. (1885) p. 200. + Comptes Rendus, c. (1885) pp. 1377-9. ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 691 this method than can be attained by employing the fringes of Fizeau and Foucault. Conversely, having measured the thickness by other means, the author has applied the formula to determine the wave- length of the ray D., and finds a value identical with Angstrém. It has been pointed out * that the author is not justified in con- cluding that the values found by Ditschreiner and Van der Willigen are incorrect, because it is not known to what degree of accuracy the thickness of the quartz plate had been measured. Dotted appearance on Pleurosigma angulatum.t—Mr. J. B. Dancer once found that the oblique markings of a damaged valve had been removed by abrasion against the cover-glass ; by no modification of the light could they be rendered visible. When, however, oblique illumination was directed in a line with the length of the valve, the transverse markings were distinctly visible and apparently uninjured. At first he thought that moisture had obtained access through the crack in the thin cover, and he dried the slide over the flame of a spirit-lamp carefully and repeatedly, but could not make the oblique lines visible, although they were distinctly visible on other broken - valves contiguous to the special one under examination, and also on some portions of this valve; the oblique markings which had been dislodged were lying beside the edge of the damaged valve. Reason- ing from what he had seen, he was led to imagine that the oblique markings were on the upper convex surface of the valve, and that the transverse markings were on the inside or concave surface. If we assume that the section of these raised markings are semi-cylindrical in form—that is, being rounded at the top—there would be an im- perfect cylindrical lens formed wherever these pellucid ridges crossed the lower or transverse markings. These would present focal points of light and possibly images of objects, such as are seen in the eyes of beetles under certain conditions of illumination ; if this be true, the so-called beads have no existence. Mr. Dancer in a subsequent communication t writes as follows :— “In my letter of the 28th May, I assume that the cross section of the ridges or markings on P. angulatum are semi-cylindrical, and also state that the A. pellucida ridges would form imperfect cylindrical lenses, where they cross the lower transverse markings. ‘To render my meaning more intelligible, I may say that I had in my mind the jens introduced, I believe, by Chamblant, of Paris, about fifty years ago. If two pieces of polished glass, semi-cylindrical in section, have their flat surfaces placed one on the other with exactly their cylindrical surfaces at right angles to each other, a perfect lens is formed, having no spherical aberration. These lenses are much used in Paris, and occasionally in England, for hand reading-glasses and spectacle eyes. I have had such in use for both purposes for over forty years. Now, if we conceive that a number of minute lenses of this form were placed in juxtaposition, and examined under a Microscope, they would show images of any objects placed between the mirror and the * Zeitschr. f. Instrumentenk., v. (1885) p. 325. ft Engl. Mech., xliii, (1886) p. 283. t Ibid., p. 329. 2% 2 692 SUMMARY OF CURRENT RESEARCHES RELATING TO source of the illumination; in fact, they would exhibit the same appearances as those presented by the eye of a beetle when viewed microscopically. From this we may assume that when the markings on diatoms are exactly at right angles, the most perfect lenticular performance would be visible. A very pretty microscopic object may be produced in the follow- ing manner :—Place a metal ring on a slip of glass; in the centre of the metal ring put a minute quantity of the flowers of sulphur, and place a thin cover-glass over the metal ring; then hold the strip of glass at some distance above the flame of a spirit-lamp, in order to sublime the sulphur; when the slip of glass is placed under the Microscope, and viewed with a moderately low power, the sublimed sulphur will appear as minute plano-convex lenses, in which the image of an object placed between the mirror and the source of light will be beautifully shown. These plano lenses will remain trans- parent so long as the cover-glass is kept moderately warm. When cooling, the act of crystallization may be observed ; when cold, these minute hemispheres are opaque. It may be necessary to repeat the experiment to insure the best results. If too much sulphur, or too much heat, the lenses are not microscopic. By blowing through a heated glass tube, on to the surface of the cover-glass, the act of crystallization can be retarded.” “ Central v. Oblique Light.”—Mr. E. M. Nelson thinks* that he has been hardly dealt with by the “ Royal Microscopical Society,” t who in place of meeting his “criticisms en their teaching” in a proper scientific spirit, have made a “ personal attack” upon him and are threatening him with their sledge-hammer. This is the story of the wolf and the lamb in an intensified form. How criticism should be met depends upon circumstances, and there are occasions when “ personal attack ” (adopting Mr. Nelson’s term) is the only remedy, except silence, which is open to the agerieved party. Suppose Mr. Nelson had, for instance, published a statement ex- pressive of his regret that Prof. Huxley was so determined an opponent of Darwinism, and that, in consequence, he intended to demonstrate the falsity of the Professor’s teaching. Does he suppose that Professor Huxley would proceed to discuss the matter in a “proper scientific spirit,’ or that if in place of treating it with silent contempt (as he probably would) he made a “ personal attack” by way of reply, would any one consider it as otherwise than well-deserved ? But Mr. Nelson has gone much further even than the case we have put. When he first misrepresented the “ Royal Microscopical Society” as teaching the views which he combated, we pointed out that not only were those views not held as suggested, but that we had never met or heard of any one who holds or had ever held them. In decent society it is usual, when a person has disclaimed an opinion improperly attributed to him, to do one of two things—either to with- draw it (with or without an expression of regret at having made it, * Engl. Mech., xliii. (1886) p. 300. t See note supra, p. 574. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 693 according to the taste or temperament of the person guilty of the misrepresentation), or to substantiate it by a complete demonstration. Mr. Nelson has attempted the latter alternative in a way which we will not characterize, but which can be properly appreciated from what follows. Mr. Nelson’s original statement, it will be remembered, was that the “Royal Microscopical Society” taught that “nothing can be “known about the structure of the diatomaces because all the diffrac- “tion spectra are not admitted,” a proposition which is so absurd on the face of it, that we find it impossible to believe that Mr. Nelson can have honestly supposed it to be held by any human being of only average intelligence, much less taught by the “ Royal Microscopical Society.” The proof of his assertion Mr. Nelson gives as follows :— “Whether, for example, P. angulatum possesses two or three sets of strie, whether striation exist at all, whether the visible delineation is caused by isolated prominences, or depressions, &c., no Microscope how- ever perfect, no amplification however magnified, can inform us. Mon. Micr. Journ., xiv. 1875, p. 250.” : Thus, although the pages of this Journal teem with passages which show that the views attributed to the Society are purely imaginary, Mr. Nelson passes over every one of them, even the authoritative paper of Prof. Abbe himself, and goes back more than ten years to cite a paragraph from the Monthly Microscopical Journal, which, as is well known, was an independent publication not under the control of the Society. Ts that a course of proceeding which entitles its author to demand that he should be dealt with in a purely scientific spirit ? Moreover, the paragraph quoted, as will be seen, in no way sup- ports Mr. Nelson’s original statement, or shows that any one, much less this Society, ever taught that unless all the diffraction spectra are admitted nothing can be known of the structure of the diatom- acew. The Fellows of this Society hardly require to be reminded of what the diffraction theory really does teach, viz. first, that according to the coarseness or fineness of the structure, a greater or less number of the spectra are admitted, and secondly, that the greater the number admitted, the nearer will the image resemble the object. Were we far wrong in saying that a writer had mastered but little of the diffraction theory, who could sweep together the diatomacee in general—the coarse as well as the fine—as is done in Mr. Nelson’s original statement, and who was further so oblivious of what has been said as to the indications of structure given by even a portion of a set of spectra as to write that this Society taught that “ nothing can be known of the structure of the diatomacez, because “ all the dif- fraction spectra are not admitted” ? As we said before, it was so much.of a puzzle to us to comprehend why Mr. Nelson should go so far out of his way to try and fasten upon people views which existed only in his own imagination that we could only account for it by the supposition that he had been led away by the practice well known in other quarters to which we 694 SUMMARY OF CURRENT RESEARCHES RELATING TO referred, and had attributed to the Society the most absurd views for the purpose of glorifying himself by showing how he could dispose of them. We fail to see the good of such tactics, for even if for the time the writer is able to pose as a victor, the victory in a few weeks is turned into worse than a defeat when the demonstration of the dis- creditable arts to which he has had to resort is published. Mr. Nelson deprecates the sledge-hammer being applied to him, We shall be only too glad to put the sledge-hammer back in its place when he returns to the usages not only of scientific but of all decent persons, and abstains from the misrepresentations in which he has recently indulged. Interpretation of the Six Spectra of Pleurosigma angulatum. This article by Mr. E. M. Nelson* is the most striking instance which we can recall, at any rate in microscopical matters, of a critic being “ hoist by his own petard.” The article purports to show the error of the view of Dr. Eichhorn in his paper on this subject, referred to in this Journal, I. (1878) p. 186, and while to some extent excusing Dr. Eichhorn for his mistake, insists that the support given to him by “the R.ML.S. is quite un- pardonable.” Now, the simple fact is that Mr. Nelson has found a most egre- gious mare’s-nest. The very thing that Mr. Nelson declares Dr. Eichhorn ought to have said, but did not say, he does say. The very thing that Mr. Nelson considers Dr. Eichhorn to be wrong in saying, he does not say. Mr. Nelson has mixed up the images seen in the Microscope and the real structure of the objects which furnish those images, so that while Dr. Eichhorn who had “never seen a diatom” (as Mr. Nelson himself says) deals necessarily exclusively with images, and those false ones, he is denounced for his fallacies in dealing with true struc- tures ; and this Society, who for many years have published in every number of the Journal a table showing how many lines to the inch can be resolved with a given aperture, are supposed to believe than an aperture of 0:50 N.A. will resolve 100,000 per inch ! f All this arises from the fact that Mr. Nelson has never read the paper which he elaborately criticizes, either in the original German or translation. This is a strong assertion to make, and we should not venture to do so at second-hand, or if we had not extracted the admission from Mr. Nelson himself. * Engl. Mech., xliii. (1886) pp. 337-8 (5 figs.) and 396. + It would hardly be fair to deal seriatim with the various mistakes of Mr, Nelson’s paper as they all flow from the one cardinal error of supposing that Dr. Eichhorn had predicted “true markings” in place of admittedly false images, but there is one matter of fact which should be corrected. Mr. Nelson declares that the points in question cannot be seen in the way described, but only by enlarging the diameter of the dioptric beam and cutting out the six spectra, “and until they are cut out nothing will be seen of the intercostal markings.” The simple fact is that they were seen by Prof. Abbe, Mr. Stephenson, and other Fellows with a very narrow dioptric beam and without one of the six spectra being cut out. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 695 The best, however, remains to be told. Mr. Nelson expresses his astonishment that it was not seen that “ insistance on the accuracy of Dr. Eichhorn’s interpretation stultifies Prof. Abbe’s magnificent diffrac- tion theory.” Now the problem solved by Dr. Eichhorn was set to him by Prof. Abbe himself; the solution was printed and published under his auspices; and it was sent by him to the Society as a re- markable confirmation of the diffraction theory! As the paper in this Journal from which Mr. Nelson quotes plainly states the part which Prof. Abbe’s University took in the matter, the wonder is that no suspicion crossed Mr. Nelson’s mind when he was writing as to the error into which he had fallen. It was hardly likely that any Uni- versity would take the pains to make public the work of a student which “ stultified the whole of the magnificent theory” of one of their most illustrious professors ! Mr. Nelson’s mistake has its origin, we fear, in another attempt to throw a stone at the “ Royal Microscopical Society.” We are hardly called upon to repress a feeling of satisfaction that it should have resulted in so notable a miss. ALLISON, F. B.—See Dancer, J. B. American Society of Microscopists.—Ninth Annual Meeting. [Circulars issued by the President, Secretary, and Director of Working Session. : Amer. Mon. Micr. Journ., VII. (1886) pp. 114 and 119. Micr. Bulletin (Queen’s), III. (1886) p. 17. The Microscope, VI. (1886) pp. 124-8. Auckland (N.Z.) Microscopical Society, First Annual Meeting of. Journ. of Micr., V. (1886) p. 196. B., L. B.—True cause of dotted appearance in P. formosum. Engl. Mech., XIII. (1886) p. 300-1. BERTRAND, E.—Nouvelles dispositions du Microscope permettant de mésurer Vécartement des axes optiques et les indices de refraction. (New arrangement of the Microscope allowing of the measurement of the separation of the optic axes and the indices of refraction.) [Post.] Bull. Soc. Minéral, de France, VIII. (1885) p. 377. A 5 Sur la Mésure des indices de réfraction des elements micros- copiques des Roches. (On the measurement of the indices of refraction of the microscopic elements of rocks.) [Post.] Ibid., p. 426. BuieEeKkrope, L.—See Thompson, G. Curter, E.—Cam Fine Adjustment? [Post.] The Microscope, V1. (1886) pp. 101-4 (1 fig.). Dancer, J. B—What is the true cause of the dotted appearance on the P. angulatum. ([Supra, p. 691.] Engl, Mech., XLIII. (1886) p. 283 and 329. See also F, B. Allison, p. 35]. Dancer (J. B.), Proposed Annuity for. [Statement of his services to science. ‘“ He invented microscopic photo- graphs, which so much delighted and astonished us twenty-five or thirty years ago,” and brought out excellent Microscopes moderate in price. ] Nature, XXXIV. (1886) p. 200. DirvupoNN»s, E.—De l’Electro-mégaloscopie. (On electro-megaloscopy.) [Post.] La Lumiére Electrique, XIX. (1886) pp. 64-7 (8 figs.). Directory, Science. [Microscopical and other Societies, contd.] Sci.-Gossip, 1886, p. 138. 696 SUMMARY OF OURRENT RESEARCHES RELATING TO Eweut, M. D.—On Fine Measurements. (Criticism of Dr. Shanks’ blood measurements, supra, p. 529.) Amer. Mon. Micr. Journ., VIL. (1886) pp. 119-20. Exner, S.—UVeber Cylinder, welche optische Bilder entwerfen. (On cylinders which form optical images.) [Post.] Arch. f. d. Gesammt. Physiol, XX XVIII. (1886) pp. 274-90 (10 figs.). Eaner’s Repert. d. Physik, XXII. (1886) pp. 299-313 (10 figs.). FrANcoTTE, P.—Description du nouveau Microscope a dissection de Zeiss. (Description of Zeiss’s new dissecting Microscope.) [Ante, p. 507.) Bull. Soc. Belg. Micr., XII. (1886) pp. 79-82 (1 fig.). Gites, G. W. M.—On Marine Collecting with the surface net. [Dises of vulcanite for use with lieberkiihn, supra, p. 681. ] Sci.-Gossip, 1886, p. 121. GLADSTONE, J. H.—See Thompson, G. GorTnarp, E. v.—Apparate fiir Aufnahmen himmlischer Objecte. (Apparatus for photographs of celestial objects.) [Describes the application of a Microscope to a telescopic camera for focusing. : Zeitschr. f. Instrumentenk., VI. (1886) pp. 5-14 (10 figs.). Harninatron, M. W.—The Microscope and the Telescope. [Reply to the question what is the difference between them.] The Microscope, VI. (1886) pp. 106-7. Henocqun—Appareils destinés a l’examen du sang. (Apparatus for the ex- amination of the blood.) [The apparatus (resembling Donné’s lactoscope and Hermann’s hemato- scope) allows of the examination of undiluted blood, which is placed between two plates of glass which have a triangular prismatic space between them varying from 0 to a third of a millimetre. The advan- tages claimed are that the blood does not require to be diluted, a minimum quantity only of blood is required to be used, and above all, it is not necessary to have recourse to the comparison of different tints. The plates can be applied to any spectroscope, and oxyhsemoglobin, hemoglobin, and methemoglobin can be successfully studied.] Journ. Soc. Scientifiques, I. (1885) p. 24. (Soc. de Biologie 11th Jan.) [H1rconucock, R.]—Microscopical Exhibitions. (‘It is undoubtedly true that the efforts of any committee to please all the members of a society are fruitless, for there will always be some dis- affected ones. It is impossible to know just what everybody wants, until somebody is assigned to a part that he does not want. Then, when too late to make any changes, the committee learns that such a person will not be present. ‘This is one of the difficulties in arranging a systematic display of this kind. Some persons will not sacrifice personal interests to the wishes of a majority. They seem to think they should be per- mitted to show what will probably give them most notoriety, or attract most general attention to their work. Not being allowed to do that, they stay away entirely.” ] Amer. Mon. Micr. Journ., VII. (1886) p. 117. Hoéerau, E. v.—Die achromatische Wirkung der Okulare von Ramsden. (The achromatic action of the Ramsden eye-pieces.) Central-Ztg. f. Optik u. Mech., VII. (1886) pp. 110-1. JENNINGS, J. H—[Photo-micrography, or] how to photograph Microscopic Objects; or lessons in Photo-micrography for beginners. And a chapter on preparing Bacteria, by R. L. Maddox. viii. and 128 pp. and 30 figs. (8vo, London, 1886). (Reprinted from the ‘Photographic News,’ with many additions.) Mayer, A. M.—On the Well-Spherometer; an instrument that measures the radius of curvature of a lens of any linear aperture. Amer. Journ. of Sci., XXXII. (1886) pp. 61-9 (7 figs.). Mies, J. L. W.—President’s Address [to the Manchester Microscopical Society ]. [Deals mainly with illumination. ] Ann. Report for 1885 (1886) pp. 15-25. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 697 NE son, E. M.—Central v. Oblique Light. (Supra, p. 692.] Engl. Mech., XUIII. (1886) p. 300. The resolution of Diatoms Whose striz are of unequal fineness. "TPost.)” Tbid., p. 828 (1 fig.), p. 396. 5 + The interpretation of the Six Spectra of Pleurosigma angulatum. [Supra, p. 694.] Ibid., pp. 337-8 (5 figs.), p. 396. Objectives, New. [The new 1/8 in. objectives of Zeiss, made of the new glass, will be in the market very soon—indeed, they are expecting daily to receive a supply. Hereafter Mr. Zeiss will not make any more of the celebrated 1/18 in. objectives, but will provide another lens to take its place.” Amer. Mon. Micr. Journ., VII. (1886) p. 118. PELLETAN, J.—La Théorie du Microscope et l’Optique simplifiee. (The theory of the Microscope and simplified optics.) [Characteristic introduction to a series of articles intended to be published on simplified optics. } Journ. de Microgr., X. (1886) pp. 279-85. Piersol’s (G. A.) Photograph of Bacillus tuberculosis. [x 1090—*shown as clear and distinct as when viewed with the Micro- scope.” ee Amer. Mon. Micr. Journ., VII. (1886) pp. 99. Queen’s (J. W. & Co.) Acme No. 4. Microscope. [Post.] ? Micr. Bull. (Queen’s), ILI. (1886) p. 17 (1 pl. and 1 fig.). Resolving 152,000 lines to the inch. [Correspondent thinks that “with a little patience it could be accomplished, for I have already resolved 140,000 with the same objective and illu- mination ! ”] Micr, Bull. (Queen’s) ITI. (1886) p. 14. Royston-Prcort, G. W.—Microscopical Advances. XI., XII. {Diatomic beading and images. Diatomic colours. ] Engl. Mech., XLII. (1886) pp. 313-4 (7 figs.), pp. 383-4 (2 figs.). [Royston-Picort, G, W.]—Delicate Fine Focussing Adjustment. [ Supra, p. 686.] Engl, Mech., XLITI. (1886) p. 340 (2 figs.). S., H. G. F.—A Concentric Microscope. [Moditications in Cox’s Microscope with concentric movements * would give it the essential features of the best known English and American Micro- scopes. (1) The tail-piece (preferably one only) should have a clamp above the stage to fix it parallel to the optic axis; (2) the mirror-bar should be removable, and arranged to clamp on one of the feet of the base; (3) the stage should have mechanical movements like ‘‘ Watson’s or Ross’s best diatom stage”; and (4) a “combination condenser” like Swift’s or Pillischer’s should be applied. “The concentric or radial construction . . . gives such extreme stability at every angle of inclina- tion that . . . it seems destined to supersede the ‘Jackson’ model, as that superseded the ‘ Ross’ with the majority of makers.” Engl, Mech., XLII. (1886) p. 352 (2 figs.), p. 375. THIESEN, M.—Ueber die Ablesung von Normalbarometern und itiberhaupt von grosseren Fliissigkeitsoberflachen. (On the reading of normal barometers and large fluid surfaces.) [The difficulty of exact readings where the surface of the mercury is large has led to various contrivances based on the principle that the distance between an object and its image seen in a plane reflecting surface is bisected by the surface. Marek substituted for Pernet’s fixed index the image of a horizontal thread thrown by a lens into the centre of the tube; but the results obtained are not satisfactory. Dr. Thiesen uses the scale at the back of the tube as the object; the reading for the surface of the mercury is then found by a simple micrometric measurement of the dis- * Cf. this Journal, iv. (1884) pp. 279-81. 698 SUMMARY OF CURRENT RESEARCHES RELATING TO tance between a division on the scale and its reflected image. If, e.g., the distance between 771 mm. and its image measured in fractions of one of the visible intervals is 1:4 mm., then the true reading is 771°7 mm. A great advantage of the method is that it obviates all cathetometer adjustments and errors. The errors introduced by refraction through parts of the glass tube, while not entirely eliminated, are less pronounced than in other methods. } Zeitschr. f. Instrumentenk., VI. (1886) pp. 89-93 (4 figs.). Tuompson, G.—The determination of the Index of Refraction of a fluid by means of the Microscope. Nature, XXXIV. (1886) pp. 157 and 217. Also criticisms by J. H. Gladstone and L. Bleekrode, pp. 192 and 290. Tuompson, 8S. P.—Notes on some new Polarizing Prisms. (1. Ahrens’, ante, p. 397. 2. Simple modification of the Nicol prism, giving wider angle of field. Post. ] ; Phil. Mag., 1886, pp. 476-80 (1 pl.). To1son, J.—Eclairage intensif en micrographie. (Condensed illumination in microscopy.) (Suggests as a substitute for the Abbe condenser an objective—1/7 in. 0°94 N.A.—fixed in the cylinder diaphragm-holder. ] Journ, Sci. Méd. Lille, 1885, 5 pp. Wa uaokr, E., Jun.—The Amateur Photographer: A Manual of Photographic Manipulation, intended especially for Beginners and Amateurs. 205 pp., 1 phot., and figs. (Svo, Philadelphia). WaTERHOUSE, A.—Blood Measurements. [Table of measurements of blood-corpuscles of various species of Mammals]. The Microscope, V1. (1886) pp. 97-101. Weyers, J. L.—Le Microscope Entomologique. (The Entomological Micro- scope.) CR. Soc. Entomol. Belg., 1886, No. 71, pp. X¢.-xciil. f. Collecting, Mounting and Examining Objects, &c.* Histophysics of the Red Blood-corpuscles.;—Drs. S. J. Meltzer and W. H. Welch have had occasion in the course of their investiga- tion on the colouring matter of the blood, to search for the remains of the uncoloured red blood-cells, the so-called phantoms. Their experience was that these can be rendered more evident by means of certain substances capable of coagulating albumen, such as prussic acid (saturated solution), pyrogallic acid (20 per cent.), copper sul- phate (10 per cent.), chlorate of potash (6 per cent.), silver nitrate (3 per cent.). The phantom corpuscles appear as dark rings; on the application of chlorate of potash as pale bluish discs. The last three reagents have the advantage of not altering blood-corpuscles present with the phantoms. Counting Blood-corpuscles.t—For counting white blood-cor- puscles M. J. Toison adopted the staining method, using the basic anilins, of which he found methyl-violet 5 B the most reliable. The formula given is:—Distilled water, 160 c.cm.; glycerin at * This subdivision contains (1) Collecting Objects; (2) Preparing, (a) in general, (b) special objects; (3) Separate processes prior to making sections; (4) Cutting, including Imbedding and Microtomes; (5) Staining and Injecting ; (6) Mounting, including preservative fluids, cells, slides, and cabinets; (7) Ex- amining objects, including Testing ; (8) Miscellaneous matters. + Centralbl. f. d. Med. Wiss., 1884, p. 721. t Journ. Sci. Med. de Lille, 1885, 4 pp. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 699 30°, 30 c.em.; soda sulphate, 8 grms. ; soda chloride, 1 grm.; methyl- violet 5 B, 0:025 grm. The violet was dissolved in the glycerin, diluted with half the distilled water, the salts in the other half; the two mixed and filtered when cool. The staining fluid was mixed with the blood and then placed in a cell or moist chamber. The staining action is well marked in 5 to 10 minutes, and attains its maximum in 20 to 30 minutes. The white blood-corpuscles appear as small granular violet balls, which are easily distinguished from the greenish coloured red corpuscles. Obtaining Hemoglobin Crystals.*—Dr. St. v. Stein places a thin layer of fresh defibrinated blood upon a slide, and when it begins to dry at the edges, covers it over with Canada balsam, which should not be tco fluid as the crystals are then less permanent. As long as the balsamic odour is perceptible, the specimens remain without a cover- glass. The balsam layer is then removed by means of a knife moistened with ether, turpentine, or oil of cloves. A cover-glass is put on and sealed up with balsam or asphalte. Such preparations have kept well for ten years. Preparing Muscle to show Nerve Extension.j—The procedure used by Dr. R. Mays for making preparations to show nerve extension in muscle is a combination of the osmic acid method with gold staining. The addition of the gold salt is to prevent the browning and clouding of the muscle substance, which occurs after osmic acid only, associated with the previous swelling of the muscle in dilute hydrochloric acid. Dr. Mays’ procedure with thin muscle from which he obtained suitable preparations is as follows :— The fresh muscle is placed in a mixture of 0°5 per cent. gold chloride solution (1 part), 2 per cent. hyperosmic acid (1 part), and water 50 parts. It is then cleared up in a mixture of glycerin 40 parts, water 20 parts, and 25 per cent. hydrochloric acid, 1 part. This procedure does not, however, prevent clouding and browning in thick muscles. To avoid these inconveniences altogether, Dr. Mays recommends the following method. The fresh muscle is laid for 12 hours in a 2 per cent. solution of acetic acid, then for 2 to 3 hours in the gold-osmium solution (0°5 per cent. gold chloride solution 1, 2 per cent. osmic acid 1, 2 per cent. acetic acid 50). For clearing up the above, glycerin mixture is used. Although the foregoing methods give excellent results, they fail to distinguish between the intra- and hypolemmal parts of muscle; but in an appendix Dr. Mays adds a method by which this differentiation becomes possible and which shows that by the gold-osmic-acid treat- ment the nerve-fibres are stained to their ends, i.e. up to their entrance into the muscle. The muscle is thoroughly soaked in a 0-5 per cent. solution of arsenious acid, and then for 20 minutes in a freshly made mixture of 1 per cent. gold chloride, 4 parts; 2 per * Centralbl. Med. Wiss., 1884, p. 404. i + Zeitschr. f. Biol, xx. p. 449. Cf. Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 401-2. 700 SUMMARY OF CURRENT RESEARCHES RELATING TO cent. osmic acid, 1 part; 5 per cent. arsenic acid, 20 parts. The muscle having been washed, is exposed for three hours to the sun- light at a temperature of 45° in a bath of 1 per cent. arsenic acid solution. The glycerin and hydrochloric acid mixture is used for clearing up. In successful preparations the nerve with its hypo- lemmal parts is stained throughout. Demonstrating Nerve-endings in Striated Muscular Fibre of Man.*—For this purpose Prof. M. Flesch proceeds as follows :— The muscles are placed as soon as possible post mortem in a 0:5 per cent. gold chloride solution until they appear of a straw yellow colour; they are then exposed to the light in dilute acetic or formic acid. After reduction has taken place, the muscle is ready for examination. Hardening is done in alcohol and imbedding in tallow and paraffin without previous saturation with turpentine or chloro- form. The author calls attention to the fact that in one and the same specimen, differences of staining are discernible after treatment with gold chloride; these in some measure depend upon the unequal saturation of the muscle with the gold solution, but in greater part are to be referred to structural differences of the muscular fibres. Differ- ences of staining in reference to intensity and quality are distin- guished, the former depending on the histological non-equivalence of individual fibres; the latter consisting in the staining showing every transition stage from rose through purple-red, and violet to pure blue. Demonstrating an Endothelial Element of the Primitive Nerve Sheath.j—To show the intercellular substances in the vicinity of the nuclei of Schwann’s sheath, Dr. A. Gruenhagen teases out the nervus ischiadicus of the frog ; then pours over the preparation for two or three minutes some drops of a 1/2 per cent. solution of silver nitrate. He then washes with H’O, dehydrates in absolute alcohol, stains with concentrated hematoxylin, dehydrates again, and mounts in balsam. Preparing Batrachian Larve and Regulating the Circulation. {— Dr. S. Mayer describes two methods of much technical interest. The first is a process by which living larve can be fixed for microscopic research in a very short time, and this without damage, as is the case with curara injection. It consists first in passing a moderately strong current through the brain and cord, and then placing the larve in a solution of curara. By the electrization the animals are fixed in half a minute and the fixation is rendered per- manent in the curara solution, the electric palsy being at once succeeded by the curara palsy. By this means the larve can be brought in a few minutes to a condition suitable for microscopical * MT. Naturforsch. Gesell. Bern, 1885, pp. 3-25 (1 pl.). + Arch. f. Mikr. Anat., xxiii. (1884) pp. 380-1 (1 fig.). { SB. K. Akad. Wiss. Wien, xci. (1885) pp. 204-38 (3 pls.). Cf. Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 390-1. ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 701 examination, while the curara method by itself requires at least a quarter of an hour. The second procedure is a very simple method for influencing the rapidity of the blood current in the larval tail. It depends on Dr. Mayer’s observations that by the imposition of the cover-glass the blood current ceases in the covered parts of the larva, even though the cover-glass be supported at the edges by glass splinters, but that it is again restored as soon as a drop of water is run under the cover-glass. Dr. Mayer traces back these appearances to the pressure which exists in consequence of the capillary adhesion between the cover-glass and the highest point of the object. The addition of water whereby the cover-glass is removed from the object, now brings it to pass that the capillary-adhesion pressure is either diminished or altogether removed according to the size of the drop added. Accordingly in the size of the drop of water exists a means of keeping the blood current at its normal rapidity, or of diminishing it in any desired degree to complete arrest. Preparing the Radula of Cephalophorous Mollusca.*—Dr. R. Réssler places the living animals for half an hour in a moderately hot concentrated sublimate solution; then having got ready the pharynx, he treats it for another half hour with sublimate, washing thoroughly with water and staining with picro- or borax carmine, or with hematoxylin. According to the author, paraffin penetrates between the toothlets of the radula with great difficulty, and most sections are con- sequently torn in cutting. The best results were obtained by trans- ferring the object from absolute alcohol to yellow benzol, slowly adding warmed paraffin, and finally transferring to pure paraftin. The paraffin is afterwards dissolved out in benzol. Turpentine oil should be avoided, as it makes the radula brittle. Thin Sections of Entomostraca, &c.t—Dr. G. W. M. Giles de- scribes a method of obtaining thin sections of Entomostraca and other minute crustaceans, which he believes is somewhat novel. On account of their small size and the hardness of their chitinous coats, they do not lend themselves well to the paraffin method, as the knife is apt either to ride over them or to compress them, and drive out the paraffin filling up their interstices. Moreover, on account of the bulk of the apparatus and the difficulty of maintaining a constant temperature by means of spirit-lamps, it is extremely difficult in practice to carry it out on shipboard. The method described is, however, a somewhat rough and uncertain one, and it is only occa- sionally that results at all comparable to those of the paraffin method are obtained. It is, moreover, applicable only to very minute organisms. The course of procedure is as follows :—The animal is taken from absolute alcohol and immersed in oil of cloves, where it is left until it is completely clarified. It is then placed in a watch-glass * Zeitschr. f. Wiss. Zool., xli. (1885) pp. 447-82 (2 pls. and 1 fig.). See this Journal, yv. (1885) p. 434. + Sci.-Gossip., 1886, p. 122. 702 SUMMARY OF CURRENT RESEARCHES RELATING TO containing a few drops of Canada balsam (undiluted), and placed over a spirit-lamp at such a height as to melt without danger of burning the balsam. In about a quarter of an hour the balsam has driven out the clarifying agent, and penetrated throughout the entire structure of the animal. A single drop of balsam is now placed on a glass slip, and heated until it cools hard. Now take up the animal, together with a bead of balsam, on the point of a needle, and place it on the balsam on the slide, previously warmed, and prop it up in such a position that the plane of the sections desired may be parallel to that of the slide, holding it thus until the balsam has cooled sufficiently to keep it so. There is just one consistency of balsam at which it may be readily sliced with a razor, without sticking to the blade, and yet is not brittle; and it is this condition which it is desired to obtain for the bead on the slide. Accordingly, when quite cold, it should be tested with the edge of ascalpel. If too soft, the slide must be warmed over a lamp for a while; if too hard, it must be removed from the slide and replaced in the watch-glass, to which a drop of fresh balsam has been added. In the difficulty of obtaining exactly the right consistence lies the uncertainty of the method; but when this is hit upon successfully, really beautiful sections can be most easily obtained by slicing down the bead with a sharp razor or lancet, as in the ordinary hand method. The sections may be allowed to fall from the razor on to the slide until all the material is exhausted, and then covered with dilute balsam under a large cover-glass, or they may be picked up one by one on the point of a needle, and arranged in order on a separate slide, which has been varnished with a thin coat of balsam so as to retain them in their respective places while mounting. The method is also useful for obtaining sections of coralline Alge, whose structure, when deprived of their lime, is so rotten that it is extremely difficult to mount even the smallest sections whole, unless supported by some exceptionally firm imbedding material. Preparing Echinodermata.*—Dr. O. Hamann obtained good fixation without undue contraction by injecting the somatic cavity of Asteridea with a 1 per cent. chromic acid solution. When injected the animals are to be placed in a vessel containing a similar fluid. Good results were also obtained from a 1 per cent. chromic acid solution to which a few drops of a 1 per cent. osmic acid solution had been added, and also from Kleinenberg’s picro-sulphuric acid. These acids are also advantageous, because they slowly decalcify the star-fishes and therefore render them more amenable to the sublimate solution. By the use of boiling water the ambulacral feet may be obtained in their extended position, while preservative media penetrate only slowly and irregularly within the substance of the body. For staining, the author used Ranvier’s picro-carmine, also a neutral (acetic acid) carmine, Bohmer’s hematoxylin, and also * «Beitrage zur Histologie der Echinodermen, Heft 2, Die Asteriden,’ 126 pp., 7 pls. and 3 figs., 8vo, Jena, 1885. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 703 Ebrlich’s hematoxylin to which eosin had been added in the follow- ing proportion :—100 cc. Ehrlich’s logwood solution, 15 cc. of 1 per cent, watery solution of eosin. For staining maceration specimens, a methyl-green solution with acetic acid proved useful. Preserving Cilioflagellata.*—Prof. O. Biitschli preserves Cilio- flagellata in picrosulphuric acid, afterwards changing to alcohol. By this means the flagella are extremely well retained. The posterior flagellum was well observed after the action of osmic acid vapour ; but a 1 per cent. solution caused it to disappear. Mounting Foraminifera in Balsam.t—Mr. J. Carpenter gets rid of the air in Foraminifera by boiling them in dilute potash for a few moments, afterwards in pure water, and thoroughly drying them. Then put them into a test-tube with spirit of turpentine, and boil for a few minutes over a spirit-lamp. When wanted for mounting, place a drop of balsam on a slip, take up a small quantity of the shells on the point of a pen-knife or a homceopathic spoon, and immediately place in the balsam ; then put on the cover-glass, but do not use any pressure. They require baking in a slow oven for some time to thoroughly harden the balsam. Water-washed Diatoms.{—Dr. G. H. Taylor recommends the following method of preparing samples. A quantity of the mud containing the diatoms is placed in a large jar with two or three times its bulk of clean water, and thoroughly shaken up. After settling for ten minutes, about half the water is poured off into another jar, and the first is refilled, shaken, allowed to settle as before, and most of the water poured off. This is kept up until the water is perfectly clear at the end of ten minutes. The light portions poured off are saved for future treatment. The heavy material which contains all but the smallest diatoms has much sand mixed with it. To get rid of this it is shaken up in the jar of water, and the top part almost immediately poured off. This is repeated several times, refilling the jar with pure water each time until the heavy sand remaining shows but few diatoms mixed with it. The material obtained by the last pourings, consisting of nearly all the diatoms, and the fine sand, is now boiled in water with the addition of a little cooking soda, and is then placed in a large bottle filled with pure water, shaken up, and poured off after standing five minutes. The bottle is refilled, and the process continued for several hours, the time of settling being gradually reduced to three or even two minutes. The remaining material is then placed in a shallow dish, a little at a time, with a small quantity of water, and gently rocked and rotated, causing the diatoms and lighter particles to rise in the water, when they can either be poured off or dipped out with a pipette, leaving most of tho sand behind. * Morphol. Jahrb., x. (1885) pp. 529-77 (3 pls. and 4 figs.), See this Journal, ante, p. 460. + Journ. of Micr., v. (1886) p. 50. t Proc. Amer. Soc. Micr., Eighth Ann. Meeting, 1885, pp. 207-8. 704 SUMMARY OF CURRENT RESEARCHES RELATING TO Cleaning Diatoms from Marine Mud.*—Dr. G. H. Taylor places a quantity of the mud containing diatoms in a large jar, which is then filled with clean water, thoroughly shaken, and allowed to settle for ten minutes. One-half is then poured off into another jar, the first refilled, shaken up, and again allowed to settle for ten minutes, when the top portion is poured off into a third jar. This process is con- tinued with the first jar until the water is clear after settling for ten minutes. The material is then taken from the first jar in small quanti- ties, and “ sanded” by placing each portion in a shallow dish with a moderate quantity of water, and rotating the dish so as to cause a vortex in the water, when the diatoms and lighter matter will rise in the water, and can be poured off into a bottle, leaving the sand and heavier particles behind. This process is repeated with each portion until only sand is left in the dish. The “sanded” material is now placed in an evaporating dish and dried. When dry, nitric acid is poured upon it, and it is boiled until fumes cease to appear, when a few grains of bichromate of potash are dropped in, and, after boiling for a few minutes more, allowed to cool. When cool, the acid is poured off, the dish refilled with sulphuric acid, boiled, and a little bichromate of potash added. When the sulphuric acid has thoroughly cooled, it is poured off, but not into water, and the material in the dish washed two or three times with clean water, stirring it up well on each supply, and allowing it to settle each time before decanting. It is now again “sanded” by rotating the dish and pouring off the top portion of the fluid into the bottle, adding more water each time, until only sand is left in the dish. The material in the bottle, now rich in diatoms, is shaken up, allowed to settle, and the water poured off, until every trace of acid is removed, when the material is returned to the clean evaporating dish, which is nearly filled with water and boiled. A very small piece of caustic potash is now added, and the boiling continued for two or three minutes, when the contents are poured into the bottle. The material is now again washed by shaking, settling for five minutes, and pouring off most of the water, repeating the operation with fresh quantities of clean water and decreasing the period of settling to two or three minutes, until the water is free from any trace of alkali. The material is now again “ sanded ” in small quantities at a time, and the lighter portion drawn off by means of a dropping tube. The material thus withdrawn contains almost all the diatoms. When all the material has been treated in this way, it is extremely rich, containing but little sand and a small amount of vegetable silica, but may be still further improved by more time and labour. The material is washed several times in distilled or filtered ruin-water, and about five to seven minutes allowed for settling. About twenty drops of ammonia are now added, the fluid well shaken, and the washing continued as before. One or two more “ sandings” with distilled water will now give pure diatoms free from foreign matter or sand. Care should be taken not to overlook the large forms of diatoms which frequently adhere to the glass. * Proc. Amer. Soc. Micr., Eighth Ann. Meeting, 1885, pp. 208-10. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 705 Engelmann’s Bacterium-Method.*— Dr. T. W. Engelmann replies to various objections to his bacterium-method for detecting the evolution of oxygen,t especially those of Pringsheim,f{ and points out the limits to the use of the method, which cannot be applied to the quantitative determination of the oxygen evolved. He further describes the conditions most favourable for the employment of the process. The drop must contain only a single kind of bacterium, and must therefore be taken from a pure culture. The best results are obtained with a bacterium of high oxygen-requirement. The bacteria should be neither too large nor too small ; cocci of 1-2 » diam., or rods 2-3 yu in length and about 1» in diam. afford the best results. he number of individuals of the bacterium must be large enough for them to collect rapidly round the source of oxygen ; the drop should appear slightly turbid to the naked eye. During observation, evaporation must be carefully prevented from the margin of the cover-glass. Solid Nutritive Media for Bacteria.$S—M. E. de Freudenreich compares Dr. Hesse’s apparatus, for testing for Bacteria in the atmosphere, with that of Dr. Miquel, of Montsouris. In the former ‘case, air is drawn through a tube lined with gelatin; in the latter method the air is passed through water and then distributed in drops to a series of tubes containing sterilized broth. The advantage in this latter method lies in the fact that, when any alteration is observed in the broth in any one tube, this tube can be examined; whereas in Hesse’s method, in order to examine a single colony the whole apparatus has to be exposed to the atmosphere, and disturbing con- ditions may occur; and although as a rule Bacilli develope on the spot on which they fall, yet not unfrequently, and especially during summer, they may spread so rapidly that the whole of the gelatin becomes liquid. ; The author undertook numerous comparative experiments with the two methods. Out of a series of seven experiments, undertaken at the same time and place, and using peptonized gelatin in the one apparatus and peptonized beef broth in the other, he obtained the following results: Four were more favourable to the liquid medium (that is more bacteria were found by this method than by the gelatin method, in the same volume of air); one was favourable to the solid medium; two gave identical results with the two media, The author, therefore, concludes in favour on the whole of Dr. Miquel’s method ; but adds that Dr. Hesse’s is not to be neglected, on account of the ease of transport and manipulation of his apparatus. Cultivation of Comma-bacilli.||—Dr. F. Hueppe has obtained very interesting results as to the spores of the cholera bacillus by slide- cultures, which during the observations were kept at a temperature of 34°-387° C. ona hot stage. The slides used were hollow ground, so as to * Bot. Ztg., xliv. (1886) pp. 43-52, 64-9. t+ See this Journal, i. (1881) p. 962. t Ibid. § Arch. Sci. Phys. et Nat., xv. (1886) pp. 105-20. || Fortschr. d. Med., iii, (1885) p. 619. Ser. 2.—Vot. VI. 3 A 706 SUMMARY OF CURRENT RESEARCHES RELATING TO allow a sterilized cover-glass to fit over them. The nutrient media were thin layers of gelatin or agar. By this means the lively movements of the bacilli were limited as to their locality, and thus became accessible to continuous observation. Of course sufficient provision was made for the presence of air and moisture. Geissler’s parallel- walled chamber upon which very thin layers of gelatin and agar can be spread, proved of much service. For the hot stage the Lowit- Reichert modification of Stricker’s stage, for which there is a special condenser, was used. Special Criterion of Tubercle-bacilli.¥ — Dr. Voltolini states that if cover preparations of phthisical sputum be laid in strong nitric acid (1°45-1°50 sp. gr.) before staining with the Ehrlich solu- tion, the bacilli are afterwards found to have a granular moniliform appearance. The author considers this a special characteristic of tubercle-bacilli, as he has not found it in any other micro-organism, not even in the Lepra-bacillus. Application of ‘‘ Ranvier’s’ Alcohol.t—Dr. J. H. List recom- mends one-third (Ranvier) alcohol, in conjunction with 10 per cent. salt solution as the best isolation medium for pavement epithelia, one of its principal merits being that cells thus isolated stain extremely well. Ranvier’s alcohol is, however, less suitable for goblet cells which are much better studied after being treated with Miiller’s fluid or osmic acid. Schallibaum’s Collodion.t—Mr. A. B. Lee finding it stated § that it is necessary when using Schiillibaum’s fixation method to heat the slide until the oil of cloves is driven off, writes to say that this is an error, and that it is not necessary to heat the fixative to such an extent, but merely until the clove oil runs easily. For this purpose a water bath may or may not be used ; it is quite sufficient to hold the slide for a few seconds over a spirit-lamp or Bunsen’s burner, moving it to and fro the while. The procedure is as safe as it is convenient. Imbedding with Benzol and Cutting very delicate Objects.|— Dr. A. Brass after alluding to the inconveniences attending the employment of chloroform for imbedding histological preparations, strongly advocates the use of benzol for this purpose. The stained and hardened objects are first of all immersed in con- centrated alcohol, which is dehydrated by the addition of dried copper sulphate. All the water having been removed from the section the alcohol is passed off and the preparations covered over with pure benzol. The stoppered glass vessel in which the previous steps are effected, is then transferred to a water bath at a temperature of 30°, and as much finely scraped paraffin added as will dissolve. After being kept at this temperature for half an hour, the preparation is transferred to pure paraffin which is just at its melting point. To every 100 parts of paraffin about four to six parts of white wax are added. Preparations the size of a pea are left in the paraffin for * Breslauer Aerztl. Zeitschr., 1885, No. 15. + Zeitschr. f. Wiss. Mikr., ii. (1885) p. 514. t Ibid., p. 522. § Ibid., p. 571. || _Ibid., pp. 300-5, ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 707 half an hour; for larger objects a correspondingly longer time is required. The preparations thus soaked in paraffin are next allowed to set on a glass plate. ‘The sections are fixed in the usual manner by the shellac solution, and this having been done the paraffin is dis- solved out in benzol. When it is certain that all the paraffin has disappeared, Canada balsam dissolved in benzol may at once be dropped on and the cover-giass put in place. When dealing with delicate sections or with fragile and easily lacerable tissues, all disposition to tear or break up may be avoided by brushing over the upper surface of every section, as soon as it is cut, a thin layer of collodion. By this means the preparation is covered and held together by an adhesive and continuous coat. The collo- dionized surface is that which is applied to the slide. The othex steps of the process are, of course, the same as before. It may be noticed that all the author’s specimens were treated with a 5 per cent. solution of sublimate heated to 60°-70°; pieces the size of a pea are to be left in for 10 minutes; those the size of a walnut for half an hour. Thus hardened, the specimens are transferred directly to 70 to 80 per cent. alcohol for at least 12 hours, and afterwards to ‘ 90 per cent. alcohol until all traces of the sublimate have disappeared. The complete extraction of the sublimate may be known by evapo- rating a drop or two of the last spirit in a watch-glass, in order to ascertain if any acicular crystals of sublimate be deposited. The author recommends carmine for staining purposes, and the fluid he employs is made as follows:—To a large teaspoonful of carmine are added 500 grammes 70 per cent. alcohol, and to every 100 grammes of the foregoing 15 grammes pure hydrochloric acid. The mixture is then boiled for some time in a water bath. After boiling there should be a residue of carmine ; if not, add more carmine and boil again. The spirit lost by evaporation is to be replaced by 96 per cent. alcohol. The fluid, having been filtered, is ready for use. Preparations may be stained in bulk, and overstaining removed by the use of 70 per cent. alcohol. By the foregoing method the complicated karyokinetic figures and every intracellular detail can be demonstrated in the clearest manner. Sections of Teeth.*—Dr. W. C. Brittan finds that very beautiful sections of the jaws of small animals with the teeth im séu may be made in the following way :— The jaws of a well injected animal are placed for a few days in 50 per cent. alcohol, then into absolute alcohol for about two weeks, then with a fine sharp file cut away the bone from both sides of the jaw where the section is desired until, by holding to the light, the pulps of the teeth are visible, carefully keeping the piece and the file wet with alcohol during the operation. Thoroughly wash the piece with a soft brush in alcohol and place in clove oil for a few hours, or until clear. Then transfer to a very thin solution of balsam in benzole, gradually thickening the solution from day to day by adding pure balsam until the tissues are thoroughly permeated. This is an * The Microscope, vi. (1886) pp. 128-9. 708 SUMMARY OF CURRENT RESEARCHES RELATING TO important part of the process, and should not be hurried. Now place the piece in a shallow dish and add pure balsam enough to cover it and evaporate to hardness, being careful not to raise the heat above 110° F. When the balsam is hard the section may be worked down to suit. The balsam will hold the soft parts in position while this is being done. Use water as a lubricant for this part of the work. The section made to suit, dissolve out the balsam with benzole, place in absolute alcohol for a day, clear again in clove oil and mount. Sections made in this way are necessarily somewhat thick for the reason that the different parts which it is desired to show in the section seldom lie in the same plane, consequently they are best mounted in a cell ground into the slide, which allows the cover-glass to be brought down close. The method may seem somewhat tedious and certainly requires some patience, but the results more than repay for the trouble. Dammar will be found the best medium for mounting. Henking’s Microtome Object-holder for accurately adjusting the Object.t—Dr. H. Henking’s object-holder (fig. 147) aims at giving a measureable rotation to the holder by means of adjusting screws, so that sections may be cut at definite angles to one another. The clamp a, made in a curved form for convenience in holding curved objects and to avoid interference with the knife, is connected with a ball-and-socket joint contained in es, which can be fixed when necessary by the screw r. The movable half of the clamp slides upon the guides k k and is adjusted by the screw b; in the fixed half are two cylindrical holes directed accurately towards the centre of the ball joint. 7 and 7’ are two rods which slide in these holes, and their extremities are hinged at mand m’ to two long screws which are raised or lowered by the nuts d and d' fixed in position, but free to turn in the collars ¢ and ¢’. By means of these nuts, therefore, a rotation can be given to the clamp about either of the axes 7 or i’, and may be measured by divi- sions upon d andd’. The screw which works in d is only half as long as that at d’, because the object can be roughly adjusted in this direction in the jaws of the clamp, and d is only required for small motions. On the plate which covers the ball-and-socket joint is a vernier scale for indicating the thickness of the sections. By pushing the object-slide along for distances between 1 mm. and 1/40 mm., sections can be obtained without any further assistance than that of a sharp knife. * Zeitschr. f. Wiss. Mikr., i. (1884) pp. 491-6. Cf. Zeitschr. f. Instru- mentenk., y. (1885) pp. 314-5 (1 fig.). > ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 709 Staining.*—Prof. M. Flesch considers the action of staining media; first the inorganic, and secondly the organic. The action of the inorganic salts, silver, gold, iron, may be summed up by saying that the various appearances produced by metallic impregnation are to be explained partly from the physio- logical condition of the material examined, partly from various chemical affinities to particular tissue elements, and partly to differ- ences in physiological constitution. As examples of the foregoing he gives two illustrations of specimens treated with silver nitrate, one showing a section of cartilage of frog silvered en masse with a weak solution of silver nitrate, and the other giving the appearances of quite fresh cartilage of frog silvered in section with the same solution. The differences between the results are to be explained by the greater imbibition capacity of the second kind, and are not to be attributed to chemical differences. The effect of an organic stain is produced either by chemical combination or by surface attraction, i.e. by mere adhesion or in- filtration of the stain without chemical union. Examples of the former are to be found in safranin, methyl-violet, &c., in their action on amyloid substance ; in borax-carmine on hematoxylin ; in Merkel’s stain for the salivary ducts. An intermediate variety, one consisting partly of infiltration and partly of chemical union, may be found in neutral litmus solutions which stain the cell-substance red and the nuclei blue. The action of infiltration is dismissed in a few words, as Gierke’s published researches have anticipated further remarks. Dr. Flesch, however, urges that the hardening process must count for something in the result of staining processes, and concludes his paper by insisting on the significance of a physical characteristic—the unequal suscepti- bility for imbibition of the tissues and their elements—and the influence of the fixative changes on this susceptibility from imbibition of organic material. Weigert’s Hematoxylin Stain for the Central Nervous System.— Prof. M. Flesch in some comments f on his experience with Weigert’s method says that preparations which have been washed in water in the usual way, after coming from Miiller’s fluid, can be stained, pro- vided the sections (made in celloidin) are treated a few minutes in 1/2 per cent. solution chromic acid, and then, after being washed in water, placed in the colouring fluid. The sections stain very much quicker than by Weigert’s method. The decolouring process of Weigert is followed. Creosote is decidedly preferable to xylol as a clarifier. According to Dr. C. 8. Minot,t Weigert’s hematoxylin method may be used after any method of hardening and cutting, provided the sections are treated 5-15 minutes in 1 per cent. bichromate of potas- * Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 464-77 (2 figs.). + Ibid., i. (A884) pp. 564-6. t ‘Whitman’s Methods in Microscopical Anatomy and Embryology,’ 1885, p. 192. 710 SUMMARY OF CURRENT RESEARCHES RELATING TO sium, then washed in water, and transferred to the staining mixture. Instead of bichromate of potassium, the following mixture may be used with equal success, but with somewhat different results :— Water, 100 cem.; alum, 1 grm.; bichromate of potassium, 1 grm. Weigert’s Improved Method for the Central Nervous System.*— Prof. C. Weigert’s method has been adopted everywhere with great rapidity, as it offers advantages exceeding those of other methods. One of its imperfections (which has been obviated by Prof. Flesch) is that it is only applicable to preparations which have become browned by the action of chrome salts. Another is that it does not stain so many fibres (in the cerebral cortex for example) as can be shown by Exner’s osmium method. Prof. Weigert has accordingly made some further improvements which obviate this objection. The new process is as follows : — 1. The pieces fastened to a cork with celloidin are immersed in a solution of copper oxide (a saturated filtered solution of this salt diluted with an equal volume of water) and allowed to remain in an incubator for two days. It does not matter if the pieces are still brown or have become green, so long as they were once brown. More- over, if they have lain in alcohol for some time, a surface precipitate is not so easily thrown down. After the copper treatment the pieces become green, the celloidin blueish green. They may now be preserved in 80 per cent. alcohol. 2. For staining the sections the hematoxylin solution is now modified by adding a slight quantity of some alkali; it is a matter of indifference which; this addition gives it a brownish violet tone. The proportion of a saturated alkaline solution is one to one hundred of the logwood solution. In this solution the sections are placed, and owing to the action of the copper no incubator is needed. For cord sections two hours suflice; brain preparations require an immersion of twenty-four hours, in order that the fine cortical fibres may be stained. The staining solution can only be used once. For differentiation the borax and prussiate solutions must be diluted with an equal volume of water. Skatol and Carbazol, two new Reagents for Woody Fibre.t— Dr. O. Mattirolo proposes skatol and carbazol as substitutes for phloroglucin and indol as tests for wood fibre. Both of these bodies give identical reactions, i.e. they impart a violet red colour to ligneous tissue. Carbazol is doubly recommended, as it is found in commerce, and is almost altogether without odour; while skatol is so offensively malodorous that this property of itself is almost sufficient to bar its use in micro-chemistry. Carbazol, one of the products of crude anthracene, boiling between 320° and 860°, is pro- duced in the manufacture of anilin from coal. Skatol is obtained from human feces or by synthesis in the dry distillation of nitro- cuminate of barium. The author has demonstrated microscopically that skatol and * Fortschr. d. Med., iii. (1885) p. 236. Cf. Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 399-401. + Zeitschr, f. Wiss. Mikr., ii. (1885) pp. 354-5. > ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ‘ld carbazol impart a red violet colour to ligneous tissue. Sections are immersed in an alcoholic solution of these bodies for a few minutes, and having been placed in a drop of hydrochloric acid are thus examined under the Microscope. The reaction begins at once and increases in intensity after a short time. The stain, like that of phloroglucin and indol, unfortunately is not permanent. The author mentions that piridina and chinolina also give the characteristic reaction. New Fixative Medium.*—Herren C. Born and G. Wieger have found a new medium in quince-juice for fixing serial sections or for staining sections on the slide. This is free from the objections inherent to Giesbrecht’s shellac medium, Mayer’s white of egg fixative, or Schillibaum’s mixture of collodion and oil of cloves. The fixative is prepared by adding to every two volumes of quince- juice one volume of pure glycerin and a little carbolic acid to prevent the formation of fungi. The medium is applied by spreading a thin layer upon a slide; the paraffin-imbedded section is then placed thereon, and without any haste, as the glycerin prevents the adhesive layer from drying too quickly. Excess of the fixative medium should be wiped off with a clean cloth in order to prevent the section from moving about. The slide is then dried in a warm chamber at a temperature of 30°-40° C. for twenty minutes or longer. On its removal the water is found to have disappeared by evaporation, and the paraffin in a smooth layer. The parafiin is then dissolved out in turpentine and the slide is then transferred to absolute alcohol for half an hour at least. After the aleohol bath the section may be stained with any kind of dye, anilin colours for choice; it is then washed with water or spirit and cleared up in the usual way. Throughout the process the adhesion remains perfect and the fixative does not take upa trace of colour. Even under the Microscope the fixative can scarcely ever be perceived. There are two points in this manipulation which it is necessary to observe very strictly; the first is that the slide must be perfectly clean, otherwise the fixative may fail to adhere properly. It is recom- mended to lay the slides for half an hour in cold soap and water and dry them carefully with a clean cloth. The second point is that in transferring from absolute alcohol to a watery staining or washing fluid, the slide must always pass through at least one intermediate stage of alcohol, i.e. alcohol of 50°, otherwise the violence of the diffusion currents may be too strong for the fixative and cause the section to become separated from the slide. Chlorophyll for Staining.;—To the numerous vegetable products applied to staining, Dr. N. Trinkler adds chlorophyll. He obtains it from the leaves of Syringa vulgaris by extracting for twenty-four hours with alcohol, evaporating the filtered extract to dryness and dissolving this in water. The filtrate is a dark green with a trace of brown in it. * Zeitschy, f. Wiss. Mikr., ii. (1885) pp. 346-8. + Arch. f. Mikr. Anat., xxiv. (1885) p. 174. 712 SUMMARY OF CURRENT RESEARCHES RELATING TO Staining with Phenol and Logwood.—Mr. C. H. Hughes writes us as follows :— “ Phenol has now and then been referred to, but there seems to be some doubt as to its value. It is said to destroy delicate tissue and bacteria. I cannot speak decisively with regard to the bacteria, but it has no ill effect whatever on the most delicate tissue, and since I have used it successfully in staining and mounting spermatozoa (human and animal), [am entitled to think it does not destroy bac- teria, which are hardly more delicate, though of course it kills them. I put some chips of logwood in phenol, and in about half an hour have a dark-brown fluid, which stains with great rapidity, and no deposit as with the alcohol and aqueous methods. A smal) quantity of bicarbonate of soda dissolved in water is mixed with phenol, depositing copiously but leaving some still in solution, and kept as developer. The logwood stain is poured off the section and a few drops of the soda solution poured on, when a magnificent purple is developed. Young bone and attachments of muscles are wonderfully set off. Nigrosin, about 5 grains to an ounce of phenol, is unsur- passed for central system, and seems to act more much powerfully than with spirit. I have been trying for some years to effect solution of carmine in phenol. If a good solution like that of hematoxylin and nigrosin could be effected, no other dye would be needed by the histologist—for tissues, at least. Tf films of bacteria, or of spermatozoa, are exposed to Erlicki’s fluid or some of the chromic solutions for a primary effectual coagu- lation of the albumen, I am satisfied the two dyes named would be efficient in strongest solution.” Staining Pneumonia-cocci.*—Dr. Ribbert recommends the follow- ing for cover-glass preparations, viz.:—100 parts water, 50 absolute alcohol, 12 per cent. glacial acetic acid, dahlia to saturation. The covers are only just touched with the above, washed in water, and examined. Mounted in glycerin or balsam, the cocci appear deep _ blue, while the capsules are a pale blue. The stain does not last more than a few months. This method is unsuitable for sections. Staining Recurrens Spirilla in Blood-preparations.t—Dr. K. Giinther “ fixes ” very thin layers of spirilla-blood either in the flame of a spirit-lamp or in a thermostat (5 minutes), at a temperature of 75° ©. Only basic solutions of anilin dyes made with anilin water were found to have any staining power. Of these, gentian violet was found to give the most intense stain (100 ce. anilin water, 11 ce. saturated alcoholic solution of gentian violet). Before staining, it is necessary to wash the cover-glass in a solution of 5 parts acetic acid to 100 parts water for 10 seconds, and after blowing off the greater part of the acid fluid, to neutralize the rest by holding the cover- glass over an open bottle of liquor ammonie fort. for a few seconds. If this be not done, the deep staining of the blood-plasma and cor- puscles will prevent all but a very few spirilla from being seen. * Deutsch. Med. Wochenschr., 1885, p. 136. + Fortschr. d. Medicin, iii, (1885) p. 379. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ei bes After the acetic acid process, the covers are immersed in the gentian violet solution for a few seconds only, then washed carefully in water, and finally mounted in xylol balsam. Staining Capsule-Cocci.*—The difficulty experienced in staining capsule-cocci arises from the fact that the ground-substance of the preparation is so deeply coloured that the enveloping capsule is invisible, although the cocci can be discerned. This difficulty Dr. C. Friedlinder points out may be obviated by first passing the preparation thrice through the flame of a spirit-lamp, and then immersing for one or more minutes in one per cent. acetic acid. The superfluous acid fluid is blown by means of a pipette, and the preparation dried in the air is placed in the gentian violet solu- tion (100 ce. anilin water, 11 cc. saturated alcoholic solution of gentian violet) for a few seconds, washed with water, and examincd. By this process the ground-substance remains colourless, while the capsules, if any, stand out quite prominently. By cautious treatment with weak acetic acid or alcohol, the characteristic form of the sphero- bacteria sometimes appears, for the staining of the capsules is less resistant to both of these reagents than that of the bacteria them- ‘selves. In the majority of recent cases of fibrinous pneumonia, capsule- cocci can be found in the manner above indicated, but within the pneumonic exudation other Micrococci forms appear, chiefly Diplo- cocci. These forms may be distinguished from capsule-bacteria both by the want of capsule and also by their smaller dimensions. After - Staining by the Haidenhain Method.j—Prof. W. Flemming states that preparations made by this method may be much improved by after-staining with Grenacher’s alum-carmine or with Delafield’s or Béhmer’s hematoxylin. The blackened pieces, as small as possible, are after being washed in water to be immersed in the stain for two or three days, and then before cutting are to be further hardened for some hours in absolute alcohol. Sections of mucin glands stained with hematoxylin show a beautiful violet colour on these cells. It may be remarked that for successful staining the blackening should not be too intense. Nuclear Stain in Osmic Acid Preparations.{—The objection is often raised that hardening in pure osmic acid is an impediment to good staining. This inconvenience Prof. W. Flemming finds may be obviated by an after treatment with bichromate of potash, when a good stain is effected by means of Bohmer’s or Delafield’s hama- toxylin. After treatment with bichromate is, however, unnecessary if the osmic acid preparations are not kept too long in alcohol, and have not become too much darkened. They are best stained before they are transferred to alcohol. Alum-carmine also gives a good stain with osmic acid preparations in twelve to twenty-four hours. The author uses a 1 or 2 per cent. watery solution (not the vapour) of osmic acid, and hardens in the dark for about six hours, and mounts in glycerin. * Fortschr. d. Medicin, iii. (1885) p. 380. + Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 517-8. t Ibid., pp. 518-9, 714 SUMMARY OF CURRENT RESEARCHES RELATING TO Demonstration of Goblet-cells.*—For this purpose, Prof. W. Flemming recommends not only hematoxylin, which imparts a deep blue or violet colour to the contents of the goblet-cells in osmium preparations, but also the osmium mixture t followed by staining with gentian or safranin. The cell-contents then appear blue or reddish brown, and stand out sharply even under low powers. Horizontal Lathe for Grinding and Polishing hard Objects.t{— Prof. A. Eternod has a grinding lathe by which hard objects are more easily prepared than by the ordinary grindstone or the dentist’s polishing lathe. Its main feature consists in being horizontal, and it is hence very convenient to manipulate. It is made from the table of a sewing machine with its wheel and pedal. The movement is communicated by means of an endless cat- gut band running round a system of wheel pulleys. The details of the machine will be understood from fig. 148. Prof. Eternod uses emery plates and Arkansas and Turkey stones Fic. 148. for grindstones. The Turkey stone is recommended on account of the fineness of its grain for giving a perfect polish. Drainage of the fluids employed for moistening the stones is effected by means of a zine plate provided with an overflow pipe. The plate also serves to collect the sections as they leave the grindstone, and prevents the operator from being splashed. Various kinds of Slides.§—Dr. O. A. Wall describes the various kinds of slides in use, commencing with the ordinary 3 in. by 1 in., and the so-called “ French” paper-covered slides 24 in. by 3/4 in. Sections of minerals are frequently mounted on special sizes of slides, which are wider and shorter, or about 2 in, by 1} in., so as to allow a larger cover-glass to be used, and at the same time to be more easily rotated with the stage of the Microscopes made for lithological work, when the sections are to be examined with the polariscope. These * Zeitschr. f. Wiss. Mikr., ii. (1885) p. 519. ; + Cf. Zeitschr. f. Wiss. Mikr., i. (1884) p. 349, and this Journal, v. (1885) p- 554. { Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 507-9 (3 figs.). § St. Louis National Druggist, viii. (1886) pp. 24 and 39. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. tls larger slides are occasionally of use when it is desirable to mount whole sections of thick rhizomes, roots, and similar preparations. Some German workers prepare their slides by cementing very narrow strips of glass across the two ends of the slides, so that when the slides are laid upon each other, these strips prevent one slide from injuring the next one, and the slides may be packed away with- out having the ordinary grooved boxes. These slides, however, says Dr. Wall, “are not often employed in this country, for while it is true that they offer some practical advantages, they are anything but pretty in appearance, and it seems to be a pity to mount a good preparation in such a shabby manner.” “Some ornamental effects in mounting are obtainable by using coloured glass for the slides. For opaque mounts, slides of very dark-biue glass (pot-metal) present a fine background. A pretty effect is produced with some opaque objects mounted on these dark- blue slides, by illuminating with the bull’s-eye lens, and at the same time reflecting the light upwards with the mirror, thus showing the brightly illuminated object on a rich blue ground. This method is very pleasant to the eyes. If the light is not reflected upwards with the mirror, such slides appear perfectly opaque and black. Another pretty kind of slide may be made by cutting the slides from coloured glass (flashed metal), and then painting a heavy circle with varnish on the centre of the slide on the flashed side by the aid of the turntable, and then, when dry, placing a drop of hydrofluoric acid in the centre of the ring, and making a circular spot of clear glass on which the preparation may be mounted. By having slides of red, yellow, blue, purple, and other colours, prepared in this manner, quite a pleasing variety may be given to the appearance of a collection of mounted specimens. The roughness of the glass pro- duced by the acid disappears when the preparation is mounted in balsam, and, in fact, this kind of slide should only be used for balsam mounts for low powers. Still another, and very pretty slide, may be made by giving one side of a plain glass slide the appearance of ground glass, by grinding on a slab of plate glass with emery flour and turpentine. The preparation is to be mounted on the ground side with balsam. This kind of slide, like the last, is only to be used for objects for low powers. For some preparations, which should not be subjected to pressure, glass slides may be obtained, on one side of which de- pressions are ground, in which the object may le when the cover- glass is put on. These slides are to be preferred to cells for fluid mounts in many cases, but as they are expensive, they are not as frequently used as they would be if they were sold at more reasonable prices. ‘Chis might readily be done, we should think, as the grinding and polishing of these depressions is not so very expensive. The writer once had such depressions ground in a few hundred slides at 1} cents per slide; and even at twice or three times this price they would still be cheap compared with the prices commonly asked for them.