240 SUMMAKY OP CUREENT RESEARCHES RELATING TO 



brum and cerebellum, is the seat of the development of the disease, 

 Lad been disputed by Prof. V. Galtier, who found indications of virus 

 only in the lingual glands and on the mucous membrane of the mouth 

 and pharynx, and not in the above-named parts of dogs affected with 

 the disease. Pasteur and his comi^anions have, however, often suc- 

 cessfully inoculated the medulla oblongata, the cerebro-spinal fluid, 

 and the frontal portion of one of the hemispheres. The period of 

 incubation before manifestation of its effects has hitherto been found to 

 be uncertain, and often long, but this period can now be diminished 

 by inoculating the surface of the brain directly with pure brain sub- 

 stance removed from a mad dog : in this case, the symptoms of 

 madness, either under its silent or furious form, appear within a fort- 

 night of the operation, and death ensues in less than three weeks 

 from the same date. This method has never — as in so many other 

 cases — failed in producing the disease. 



The results of some experiments * with the active elements of 

 rabies have led Prof. Galtier to some important conclusions. Six 

 sheep and four rabbits inoculated at different times with this poison 

 by hypodermic injection all died from its effects ; while out of nine 

 sheep and one goat inoculated by intravenous injection none succumbed, 

 but on the contrary, all successfully resisted the effects of subsequent 

 inoculations. Of five rabbits which received as a draught some saliva 

 infected with virus and mixed with water, only two died. The con- 

 clusions deduced are :—(l) Intravenous injection of the poison of 

 rabies into sheep does not produce the disease, but seems to confer 

 immunity against it ; (2) introduction of the poison into the digestive 

 organs is fraught with danger. Galtier has reasons for suspecting 

 that intravenous injection, practised the day following a bite or 

 inoculation, or even the next day, will prove effectual in warding off 

 the malady. 



Lichenes. 



Nutrition of Lichens-f — G. Egeling disputes the statement that 

 when lichens grow on apparently smooth surfaces, as quartz, glass, 

 &c., they are true " epiphytes." On even the smoothest surface, 

 there are always irregularities which allow of the accumulation of 

 dust ; and from the substances which collect in this way, the lichen 

 obtains its nutriment, until it is able to decompose the hardest and 

 smoothest substances, even glass or oxide of iron. 



Thallus ofUsnea articulata.l — According to A. Jatta, the thallus 

 of this lichen consists of three distinct layers, viz. (1) a central, 

 continuous, compact, elastic, very resistant tissue, the medullary layer ; 

 (2) a much laxer and readily distinguishable tissue, composed of 

 branched hyphae and gonidia, the gonidiferous layer ; and (3) a 

 membranous sheath, very delicate and almost inelastic, the cuticular 

 layer. The interrupted or jointed thallus, characteristic of the species, 

 is the result of the unrolling of the spiral of the medullary filaments, 

 which causes their rapid elongation, in contrast to the very slight 



* Comptes Rendus, xciii. (1881) pp. 284-5. 



t Oesterr. Bot. Zeitschr., xxxi. (1881) pp. 323-4. 



X Nuov. Giorn. Bot. Itul., xiv. (1882) pp. 53-9. 



