G. GENERAL NATURAL HISTORY AND ZOOLOGY. 287 



oblongata. Death by alcohol is generally caused by paraly- 

 sis of the medulla. 12 7i, February 29, 18VG, 184. 



NATUKE OF THE INVERTEBRATE BRAIN. 



Under this heading Professor Bastian describes, in a pop- 

 uhir way, the brains of different articulated animals, begin- 

 ning with those of the lowest nematoid worms and ending 

 with those of the insects. As examples of the two extremes 

 may be first cited that of the nematoid parasitic worm, in 

 which what most nearly resembles a brain consists of a mere 

 band of nerve-fibres surroundinor the commencement of the 

 oesophagus, and containing a iQ\y nerve-cells, partly between 

 its fibres and partly in groups slightly removed therefrom. 

 In such insects as butterflies, bees, and dragon-flies, in which 

 the visual organs are enormously developed, and in which 

 the power of vigorous and sustained flight is correspondingly 

 increased, the nervous system attains its maximum of de- 

 velopment among the Arthropoda. The brain of these creat- 

 ures differs from that existinsj in all other members of the 

 class by reason of the great development of those portions 

 of it in relation with the visual organs. The " brain" proper 

 in all the invertebrate animals consists properly of but a sin- 

 gle pair of ganglia, and is in no respect homologous with the 

 brain of the vertebrates, which consists of a number of pairs 

 of ganglia forming a mass called the brain. Popidar Science 

 3IontMij, October, 1876. 



ACTION OF OZONE-WATER ON THE LOWER ORGANISMS. 



Herr Stein reports to the Natural History Society at 

 Bonn that he has confirmed the observation of Dr. Geisler, 

 that in water impregnated with ozone none of the lower or- 

 ganisms, either animal or vegetable, can develop; that, in 

 fact, if they are present, they are destroyed, and without any 

 notable evolution of gas, but the formation principally of ni- 

 tric acid and its combinations. Having, however, been in- 

 formed that Professor Han stein had shown that the w^ater- 

 plant Elodea Canadensis had the remarkable power of de- 

 veloping oxygen, he repeated the experiment, and found that 

 the oxygen developed by this plant had the same properties 

 as ozone; so that this plant should no longer be called, as it 

 is, in German, a" water pest," but rather be known by the 



