1042 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ascogonium is then sought for under the Microscope, and the position of 

 the slide upon the stage noted by means of a piece of paper stuck thereon. 

 This device enables us to remove the slide and replace it under the bell-jar 

 for further growth, and thus the stages of development may be examined 

 vpithout difficulty. Medium powers (Zeiss D, Oc. 4) are only available, 

 and these do not meet the requirements of all cases. If the pollinodium 

 be evident, it may perhaps be followed up with this objective. The younger 

 parts can be observed until the brown hairs appear, after which their growth 

 stops. In selecting ascogonia for observation, such as are quite immersed 

 beneath the culture-fluid must be chosen. But as the fungi stand in need 

 of much oxygen, they usually die if, when removed from the culture-drops, 

 they do not receive sufficient air. From the moment when the perithecium 

 is quite closed it becomes more difficult to follow the fate of the ascogonium. 



From very small perithecia some knowledge may be derived from cleared 

 up sections. It may then be noticed in young fruit-organs in which the 

 hyphse almost completely close up that the ascogonium is quite unchanged. 

 For further examination the assistance of the knife is required. Axial 

 longitudinal sections may be made in the following manner: — Pieces of 

 elder pith cut smooth on one side are soaked in plum decoction until quite 

 saturated therewith. The process, which is slow, may be hastened by 

 frequent and prolonged boiling. Upon the smooth side of the pieces thus 

 prepared spores are sown; these develope so that the perithecia stand 

 vertical to the pith-surface. The fungi, having sufficiently grown, the 

 piece of pith is laid in osmic acid ; after hardening they are washed and 

 then imbedded in glycerin jelly. It is also advisable to shave off a thin 

 layer which carries the perithecia and imbed it in glycerin jelly. In both 

 cases the gelatin is hardened in spirit, and then longitudinal sections of 

 the perithecia are made. Imbedding may also be made in ordinary gelatin 

 and in celloidin, but the latter is only suitable for young perithecia. 

 Orienting perithecia under a dissecting Microscope and fixation on elder pith 

 is only possible in the adult stages where the ascogonium formation has 

 already begun, as in this case there is a safe criterion between apex and 

 base. The author finds, too, apart from the fact that the ascogonium does 

 not always lie centrally, and that every axial section does not afford correct 

 information as to the relation of the carpogonium, that it is difficult to 

 decide whether a section is accurately axial or not. 



Osmic acid facilitates the examination, as it stains the hyphsB of the 

 carpogonium brown or brownish yellow. The same colouring also appears 

 in the old cells which proceed from the ascogonium. 



Some Novelties in Bacteriological Apparatus.*— (1) New form of 

 Incubator. — Dr. M. Schottelius has devised an incubator which, though 

 unprovided with a gas-pressure or thermo-regulator, does not vary summer 

 or winter more than 0"15°. The incubator contains two approximately 

 cubical compartments (50 cm.), and consists of a double-walled box of zinc 

 plate 1 • 37 m. long, • 80 m. deep, and • 80 m. high. Between the double 

 walls circulates a layer of water 10 cm. thick, except at the top, where 

 the layer is 20 cm. thick. The box is subdivided by a median partition, 

 also double-walled and filled with water. The capacity of each chamber 

 is therefore about 1/8 cubic metre. Access to the chamber is obtained by 

 two double- walled zinc doors filled with a layer of ashes 10 cm. thick. 

 The doors are placed at opposite ends of the long sides of the incubator. 

 At the lower part of one of the shorter sides is a tap for letting off the 

 water. Between the inner wall of the door and the incubator space is a 



* Ccutnilbl. f. Bacteriol. u. Parasitenk., ii. (1887) pp. 97-102. 



