SCIENCE. 



57 



be found incapable of prcducirg the feeblest develop- 

 ment. Perfectly limpid at first, the liquid remains in- 

 definitely limpid. 



We are led to believe that the cultivation of the attenu- 

 ated virus in a chicken places its body in the same state 

 as that of the liquid which can no longer sustain the life 

 of the germ of disease. We may extend the comparison 

 still further, for, if we filter the broth on the stcond day 

 of the cultivation, instead of on the fourth, the filtered 

 liquid will still permit the cultivation of the germ, but 

 less readily than at first. This may enable us to under- 

 stand that the cultivation of the attenuated germ in the 

 body of a chicken may not have removed all the food for 

 the germ. The remainder may allow a fresh cultivation 

 of a feebler kind. This is the same as a first vaccina- 

 tion. Subsequent inoculations will remove progressively 

 all the materials for the cultivation of the parasite. 

 Through the action of the circulation, a time will come 

 when any new cultivation on the animal will remain un- 

 productive. Then the disease cannot recidivate, and the 

 subject becomes perfectly vaccinated. 



It may seem astonishing that the first cultivation could 

 have stopped before all the food of the germ has betn 

 destroyed ; but we must not forget that the germ is 

 aerobian,! and that, in the body of an animal, it does not 

 find the same conditions as in an artificial medium of 

 cultivation, in which there are no obstacles to its propa- 

 gation. In the body, on the contrary, it finds opposition 

 from the cells of the organs, which are also aerobian, and 

 are continually absorbing oxygen. 



We might also account for the fact of non-recidivation 

 by admitting that the life of the germ, instead of destroy- 

 ing certain substances in the body of an animal, on the 

 contrary, adds other substances which act as an obstacle 

 to its further development. The history of the life of 

 these inferior beings, of all beings in fact, authorizes this 

 supposition. The excretions due to vital functions often 

 prevent vital functions of the same nature. In some fer- 

 mentations, antiseptic products are formed while fermen- 

 tation is going on, and even by the action of ferments, and 

 these products put an end to further action, even if there 

 are still substances left capable of undergoing fermentation. 

 In the cultivation of our germ, there might, in the same 

 way, be substances formed whose presence might explain 

 non-recidivation and vaccination. 



Our artificial cull ivation of the parasite will enable us to 

 examine this hypothesis. If we prepare an artificial cul- 

 tivation of the germ of chicken cholera, we may evaporate 

 the liquiu in vacuo while cold, then bring it back to its 

 original volume by the addition of chicken broth. If the 

 extract contains a poison which destroys the germ, and if 

 the presence of this poison is the cause of its non-develop- 

 ment, the cultivation of the germ cannot take place in this 

 liquid. On the contrary, the development does take 

 place without difficulty. We cannot then believe that, 

 during the life of the parasite, there are substances pro- 

 duced which prevent its further development. This is a 

 corroboration of the opinion which we have expressed on 

 the cause of non-recidivation in certain virulent diseases. 



Density of Liquid Oxygen. — J. Offret has revised Pic- 

 tet's calculation of the density of liquified oxygen and con- 

 siders the method inadmissable. His own calculation gives 

 0.840. 



Explosive Antimony. — A solution of crystalline anti- 

 mony chloride and hydrochloric acid at 1. 12 sp. gr. was 

 prepared so as to stand at 38° B. On electrolysis with the 

 Lechlanche element there was obtained in twenty to twenty- 

 four hours a most explosive deposit. — E. Mascarenas y 

 Hernandez. 



t Pasteurdivides germs and other microscopic organisms into aerobians 

 (requiring air to live) and anacrobiie (which do not'iequire air).— Trans- 

 lator . 



ASTRONOMY. 



The Roman Academy of Sciences has awarded half of. 

 the King Hubert Prize to Dr. Wilhelm Temple, Director 

 of the Acetri Observatory at Florence, for his observa- 

 tions on Nebula;. 



The second Part of Vol. II. of papers relating to the 

 Transit of Venus has recently been published by the 

 Paris Academy of Sciences. It contains, amcng ether 

 things, the last of the Memoirs relating to the expedition 

 to the island of St. Paul, the Metecrolcgy by Dr. Roche- 

 fort, and the Geological Researches made at Aden, Re- 

 union, St. Paul, Amsterdam and Seychelles, by M. 

 Velain. The first Part of Vol. III., which is to contain 

 a report of the work done at Campbell Island, is in pre- 

 paration. 



The "Reports of the Total Solar Eclipses of July 29, 

 1878, and January 11. 1880," forming Appendix HI, to 

 the "Washington Observations for 1876," has just been 

 disttibuted from the Naval Observatory. 



Owing to an error in the telegraphic dispatch, the dis- 

 coverer of Comet/, 1880, was called Pennule. It should 

 have been Dr. C. F. Pechule, of Copenhagen. The 

 comet seems to have two tails, one pointed towards the 

 sun, and the other punted about N. I5°_/. 



Astronomical Memoranda : — (Approximately 

 computed for Washington, D. C, Mondav, February 7, 

 1881.) 



Sidereal time of Mean Noon, 2i h LI™ 49 s . 

 Equation of time, I4 m 25 s . 



Mean noon preceding apparent Doon. 



The Moon crosses the meridian at about 8.30 P. M. 

 Full moon occurs on the 13th, and the last quarter on 

 the 21st of the month : — New moon on the 29th. 



Mercury is still evening star, following the sun by 

 nearly an hour. He reaches his closest position to the 

 sun on the 21st, and "greatest elongation" on the 22nd. 



Venus is still the most conspicuous object in the even- 

 ing sky. She increases her apparent distance from the 

 sun until Feb. 2o d 7 h , when she reaches "greatest elong- 

 ation " East, an angular distance of 46° 34'. 



Mars crosses the meridian at about 10 o'clock in the 

 morning. He is nearly 23 south of the equator. 



Jupiter and Saturn form with Venus an unusually 

 good opportunity for the amateur astronomer to make 

 use of his telescope in the early part of the evening. Jup- 

 iter and Venus will be in conjunction on the 21st. 



Uranus is on the meridian about two hours after 

 mid-night, and Neptune about half-past five in the after- 

 noon. Uranus is in conjunction with the moon on Feb. 

 15th. 



The Comptcs Rendu* for Jan. 3, 1881, contains a 

 paper by M. Rouget upon a method for use at sea, and 

 for travelers, explorers and others, for determining lati- 

 tude and sidereal time, dispensing with the measure- 

 ment of angles. 



Two stars are observed having at a given moment, the 

 same altitude : such observations are combined in pairs, 

 and by merely noting the time which has elapsed be- 

 tween the two observations, a simple interpolation in 

 tables prepared for the purpose will give the sidereal 

 time and the latitude of the place of observation. For- 

 mula; are given for the case mentioned above, and also 

 for deducing the latitude and sidereal time from stars 

 having the same azimuths, or azimuths differing by 180 . 

 A succeeding paper by the same author extends the for- 

 mulae to the determination of longitudes, by employing 

 observations of the moon. 



W. c, w. 



