January 14, 1892] 



NATURE 



25: 



manufactured by it. The microbe itself may disappear 

 early in the case ; but the poison formed by it pervades 

 the whole body, and especially the nervous system, and 

 produces profound and lasting effects. An early disap- 

 pearance of the microbe in influenza would explain the 

 failure to find it an post-mortem examination ; death from 

 influenza being usually the result of complications rather 

 than of the primary disease. Influenza is infectious at 

 an early stage of the disease ; but it is not known how 

 long the infectious condition may last : some cases point 

 to its being infectious as late as the eighth day, and we 

 must suppose that, as long as the disease is communicable, 

 the microbe retains its vitality. 



Evidently there is a power of resistance in the human 

 body to the invasion of the microbe, varying in different 

 persons, for not all who are exposed to the infection con- 

 tract the disease ; the resistance to it being weakened by 

 depressing influences — as fatigue, and exposure to changes 

 of temperature. 



The resistance to the poison seems also to be over- 

 come when the dose is large : a certain degree of con- 

 centration seems to be necessary in order for the disease 

 to take on an epidemic form. 



The pabulum for the microbe, or the number of sus- 

 ceptible persons, seems also to be soon exhausted ; for the 

 decline of an epidemic as regards the number of new 

 cases is often almost as rapid as its increase. At the 

 same time the immunity conferred by an attack of in- 

 fluenza is of short duration, for a person may suffer 

 repeatedly from the disease ; and the same holds as 

 regards communities, for many localities have suffered 

 repeated epidemics of influenza during the last few years ; 

 whereas an epidemic of one of the ordinary infectious 

 diseases is usually succeeded by a long period of com- 

 parative freedom. These are some of the points which 

 have to be taken account of in any theory of the causation 

 of influenza. 



During the past week the announcement has been made 

 in the public press of the discovery by Dr. Pfeiffer, in 

 the Royal Institute for Infectious Diseases at Berlin, of a 

 bacillus which he looks upon as the cause of influenza. 



It will be remembered that a similar announcement, 

 made, in January 1890, by Dr. Jolles, of Vienna, was not 

 confirmed. Since then various observers have discovered 

 in the sputa and lungs of influenza patients, micro- 

 organisms of one kind or another ; but their statements 

 are conflicting, and the forms met with are some of them 

 at least known to occur in other diseases ; so that the in- 

 ference is that they were either accidentally present, or 

 connected with secondary affections for which the attack 

 of influenza had prepared the way. Whether Dr. Pfeiffer's 

 discovery will be more successful in gaining acceptance 

 remains to be seen ; but the position of its author, and the 

 alleged confirmation of his results by Dr. Koch, will no 

 doubt secure for it a respectful consideration. 



As Dr. Koch has pointed out, in order that the relation 

 of a particular micro-organism to a particular disease, as 

 cause and effect, may be considered satisfactorily proved, 

 the following conditions must be complied with : — 



(i) The micro-organism in question must be present 

 in the secretions, blood, or diseased tissues of the subject 

 of the disease. 



(2) The micro-organisms in question must be isolated 

 and cultivated— all other organisms being excluded— in 

 suitable media outside the animal body, through several 

 generations of cultures. 



(3) The micro-organisms, thus cultivated, when intro- 

 duced into the body of a healthy animal of a susceptible 

 kind must be capable of producing in it the disease in 

 question. 



(4) In the animal in which the disease has thus been 

 produced the same micro-organism must again be found. 



It is stated that, for the investigation of the etiology of 

 influenza, a cliniqtie for influenza patients was opened in 

 NO. I 159, VOL. 45] 



September last in the Royal Institute for Infectious 

 Diseases, and that the result of the exhaustive examina- 

 tion of the cases was the discovery in the matter dis- 

 charged from the patients' lungs of a bacillus found in 

 no other cases of disease of the respiratory organs, and 

 which, as the patient recovered, gradually disappeared. 

 It is stated that the bacilli were cultivated to the fifth 

 generation, and that, inoculated into monkeys and rabbits, 

 they produced in every case the symptoms of influenza. 



It is added that these results were confirmed by Dr. 

 Koch, who further discovered the same bacillus in the 

 blood of patients in the febrile stage of influenza. 



An account of the discovery is promised in the 

 Deutsche medicinische Wochenschrift, and will be awaited 

 with interest. H. F. P. 



ON THE MA TTER THROWN UP DURING THE 

 SUBMARINE ERUPTION NORTH-WEST OF 

 PANTELLERIA, OCTOBER 1891. 

 ■V117E did not reach Pantelleria till November 5, ten 

 ^ * days after the end of the eruption, but a certain 

 number of specimens had been secured at the time by 

 people who went out in boats. Dr. Errera, who helped 

 us in other ways, kindly gave me some pieces of a bomb 

 from his own collection ; and others, among them a good- 

 sized bomb, some 30 inches in its longest diameter, were 

 obtained from the inhabitants. Out of a number of 

 small pieces from different people, I did not see any 

 that might not have formed some part of a mass such as 

 this last, and I have no evidence that any other kind of 

 material was erupted. 



General, Structural, and Mincralogical Characters. 



Ricco {Comptes rcndus, November 25, 1891) says that 

 some of the bombs had a diameter of 2 metres, and that 

 the prevailing shape was an " ellipsoid of revolution." 

 They were not only porous in texture, but contained large 

 cavities, and floated for a time, but pieces taken separ- 

 ately are fairly heavy. Ricco mentions a specific gravity 

 of I '4 (perhaps for a bomb when unbroken). A 4-ounce 

 piece of the coarser material from the inside displaced 

 less than half its weight of water, giving me specific 

 gravity 2-3. 



What most struck the possessors of specimens was 

 their coaly blackness. Nevertheless, there was on the 

 outside of the bombs a distinctly brownish layer, an 

 inch perhaps in thickness, which the eye, or better, 

 the pocket lens, shows to be due to vesiculation of the 

 transparent brown glass that here forms the ground mass. 

 In certain places vesiculation has been carried so far that 

 we have a coarse ^ type of the " thread lace scoria," de- 

 scribed among others by Dana, from Hawaii {Amer 

 Jourii. Set., March 1888, p. 213, or his book, " Character- 

 istics of Volcanoes," p. 163, 1890). 



In the brown glass of this part sections show numerous 

 narrow crystals of triclinic felspar, and in places olivine 

 and magnetite, and probably a little augite. 



Beneath this brownish layer may occur another, say 

 half an inch thick, coarser and darker than the former ; 

 but which in sections can still be seen to be for the most 

 part brown transparent glass, with the above-mentioned 

 minerals in it. 



We are thus led to a layer perhaps an inch or two 

 thick,2 coarsely spongy, black, of pitchstone lustre, which 



' I find a prettier example of this structure on one side of a piece of scoria 

 picked up last month near the base of the active cone of Vesuvius. It was 

 partly covered by the brown dust ejected since the tapping of the lava od 

 the side of the Atrio del Cavallo last summer. I do not know, therefore, 

 when it was erupted. I find on this, as on scoria that I saw erupted in 

 October 1889, a tendency to form Pele's hair (on a very small sc.ile). 



^ Unfortunately, the only whole bomb that I saw went to pieces on the 

 way to England. The point worth noticing is the difference in structure of 

 different parts ; and I give these rough measurements, taken from pieces 

 in my posses-ion, merely to show the kind of dimensions with which we are 

 dealing. 



