78 



KNOWLEDGE 



[Apbil 1, 1891. 



years ajjo, when the Angora goat was introduced, it was 

 found to be less liable to scab than the common goat. 

 The same thing has followed from great blights in the vege- 

 table world. The disastrous potato-blight caused the intro- 

 duction of many new varieties found by experience to be 

 capable of resisting the disease ; and the European vines 

 affected by phylloxera are now being replaced by different 

 kinds brought from America and other parts of the 

 world. There can be no doubt that in time this immu- 

 nity will cease, and the newly introduced variety will 

 require to be again replaced, unless some means should 

 be found of destroying the micro-organisms, which, like 

 the newly introduced animals or vegetables, will in time 

 adapt themselves to their surroundings, and perhaps acquire 

 fresh virulence thereby. 



When the investigations into disease-germs began, it 

 was thought by many that all infective diseases might be 

 prevented by inoculation, but at present the various expe- 

 riments made have not confirmed this idea except in 

 anthrax, or splenic fever, rabies, and the new remedy for 

 tuberculosis"' ; it seems, however, probable that some day 

 pleuro-pneumonia may be added to the list. For many 

 years past this disease has been successfully treated at the 

 Cape of Good Hope, and in Australia, by inoculation. 



Happily, it seems that the wide-spread infection, which 

 at one time was supposed to be likely to follow the burial 

 of an infected animal through earth-worms bringing the 

 bacilli to the surface, is not so common as was believed. 

 " Klein has pointed out that if mice and guinea-pigs which 

 have died of anthrax are kept unopened, the bacilli simply 

 degenerate and ultimately disappear " ; therefore Ur. 

 Crookshank thinks that free access to oxygen is necessary 

 to develop the spores. " Contamination of ground in which 

 diseased animals have been buried must result, therefore, 

 from bodies in which a x)ost-mortem exammation has been 

 made, by which the blood and organs have been freely 

 exposed to the air, or from animals which have not been 

 examined, owing to their hides being soiled with excretions, 

 and with blood which issues from the mouth and nostrils 

 before death." 



One of the most prominent uses of the science of bac- 

 teriology is the power gained by it of examining the water, 

 air, and soil of any place, and thus determining the num- 

 ber and character of the bacteria in any given spot. By 

 this means, places particularly subject to any given disease 

 may be avoided by those peculiarly liable to such disease, 

 and it may be, also, that eventually a means may be found 

 of destroying the pestilential bacilli, and rendering spots 

 formerly unhealthy fit for human habitation. 



Before concluding this paper, we ought to point out the 

 numbers of bacteria which have been observed to be present 

 in the air at different times and places. Miquel, who has 

 made this a special study, finds " the average number per 

 cubic metre of air for the autumn quarter at Montsouris to 

 be 142, winter quarter 49, spring quarter 85, and summer 

 quarter 10-5. In air collected 2,000 to 4,000 metres above 

 sea-level, not a single bacterium or fungus spore was fur- 

 nished ; while in ten cubic metres of air from the Rue de 

 Kivoh (Paris), the number was computed at 5.5,000. By 

 an apparatus known as ' Hesse's,' twenty-five htres of air 

 from an open square in Berlin, gave rise to three colonies 

 of bacteria and sixteen moulds ; whilst two litres from a 

 schoolroom just vacated by the scholars, gave thirty-seven 

 colonies of bacteria and thirty-three moulds." The won- 

 der is that with all these sources of disease and death con- 

 stantly with us, anyone should escape ; nevertheless, it is 



* Dr. Koch's inoculation differs from that of Pasteur in the injec- 

 tion of dead instead of living bacilli. 



an established fact that none of these micro-organisms are 

 ever found in perfectly healthy blood. The reason of this 

 is not plain. It is certain that the healthy and unhealthy 

 ahke must inhale or swallow these germs ; why should 

 they be deadly to the one and innocuous to the other '? Is 

 it because in health the white corpuscles of the blood are 

 in such a state of chemical activity as to be able to absorb 

 and consume these micro-organisms, as in the recorded 

 case of the frog ? And is it, as in the same case, only 

 when the temperature becomes raised by fever, that the 

 germs develop too rapidly for natm-al elimination '? This 

 would appear a possible exiilanatiou, but more is wanted. 

 Why, if these germs are everywhere, should we not more 

 frequently hear of the spontaneous outbreak of disease, 

 instead of finding it generally traceable to one especial 

 source '? 



THE FACE OF THE SKY FOR APRIL. 



By Herbekt S.\dler, F.E.A.S. 



THE number of sun-spots and faculw on the solar 

 disc continues steadily to increase. The zodiacal 

 light should be looked for during the first ten 

 days of the month. Conveniently observable 

 minima of Algol occur at 7h. 14m. p.m. on the 

 4th ; Oh. 7m. a.m. on the 22nd ; and 8h. o6m p.m. on the 

 24th. The following are the times of minima of some of 

 the Algol type variables aUuded to by ]Miss C'lerke in the 

 March number of Knowxedge, and which may be con- 

 veniently observed at the present time. The places are 

 for 1890. 



U Cephei (Oh. 52m. 32s.-H81° 17'). Max. 7-1 mag.; 

 min. 9-2 mag. Period, 2d. llh. 49m. 45s. April 14th, 

 Ih. 53m. A.M. ; April 19th, Ih. 32m. a.m. ; April 24th, Ih. 

 12m. A.M. ; April 29th, Oh. 52m. a.m. 



E Canis Maj. {7h. 14m. 80s. -16° 11'). Max. 59 mag. ; 

 min. 6-7 mag. Period, Id. 3h. 15m. 55s. April 2nd, 6h. 

 49m. P.M. ; April 8rd, lOh. 5m. p.m. ; April 19th, 7h. 46m. 

 P.M. ; April 28th, 9h. .52m. p.m. 



S Cancri (8h. 37m. 39s. -H9° 26'). Max. 8-2 mag.; 

 min. 9-8 mag. Period, 9d. llh. 37m. 45s. April 19th, 

 Oh. 36m. A.M. 



8 Libne (llh. 55m. 6s.— 8° 5'). Max. 5-0 mag. ; min. 

 6-2 mag. Period, 2d. 7h. 51m. 23s. April 2nd, 8h. 5:^m. 

 P.M. ; April 9th, 8h. 28m. p.m. ; April 10th, 8h. Im. p.m. ; 

 April 23rd, 7h. 36m. p.m. ; April BOth, 7h. 12m. p.m. 



U Corona- (16h. 13m. 43s. 4- 32° 3'). Max. 7-5 mag. ; 

 min. 8-9 mag. Period, 3d. lOh. 51m. 8is. April 6th, 

 Ih. 5m. A.M. ; April 12th, lOh. 47m. p.m. ; April 19th, 

 8h. 29m. P.M. 



A maximum of S Coronse (6-1 mag.— 7-8 mag. at max. ; 

 11-9 mag. -12-5 mag. at min.), which follows U Coronse 

 3m. 12s. in E.A., and is 17'-3 south of it, is due on 

 April 5 th. 



Mercury is very well placed for observation dm-ing the 

 greater part of April. On the 1st he sets at 7h. 22m. 

 P.M., or 52m. after the sun, with an apparent diameter of 

 oi" and a northern declination of 8*^ 2'. At this time he 

 will appear about as bright as Aldebaran, about f'^^f of the 

 disc being illuminated. He gradually increases in bright- 

 ness, setting on the 7th at 8h. 9m. p.m., Ih. 29m. after 

 the sun, with an apparent diameter of 6", and a northern 

 declination of 13° 20'. At this time he is considerably 

 brighter than an average first magnitude star in the same 

 position, rather less than eight-tenths of the disc being 

 illuminated. On the 11th he sets at 8h. 87m. p.m., Ih. 50m. 

 after the sun, with an apparent diameter of 6|", and a 



