468 



SCIUJVCU. 



[Vol. VI., No. 147. 



bitten by a rabid animal. Experiments are now in 

 progress to determine how long an interval may 

 elapse before the treatment ceases to be effectual. 

 This interval is at least a number of days. 



In the case of the boy Joseph Meister, who was 

 successfully treated by this method, Pasteur began 

 the inoculation sixty hours after the reception of 

 severe bites by a rabid dog. The first inoculation 

 was with a portion of spinal cord which had been 

 preserved fifteen days. The treatment lasted for 

 ten days ; in all, thirteen inoculations were made, 

 each one with a cord one day fresher than that 

 used in the preceding inoculation ; at the last in- 

 oculation there was used a cord preserved only one 

 day, and containing a virus which produced rabies 

 in a rabbit in seven days ; that is, a virus more 

 malignant than that in the bite of a dog affected 

 with the rabies of the streets. The boy was kept 

 under observation, and at the time of Pasteur's 

 communication — three months and three weeks 

 after the bite — no symptoms had developed. 



After Pasteur's communication, Vulpian advised 

 that a service be organized for the treatment of 

 rabies by Pasteur's method. 



Pasteur is unable to explain in what way im- 

 munity is produced by his method of inoculation. 

 He thinks that the virus is altered in quantity 

 rather than in quality by his method of preserving 

 the cords. He notes the interesting fact, that, if 

 the cords are preserved in a moist atmosphere of 

 carbonic acid, with oxygen excluded, the original 

 virulence remains unchanged, even after several 

 months. 



The fuU detaOs of Pasteur's experiments upon 

 animals, with description of sjrmptoms and of 

 post-mortem examinations, wiU be awaited with 

 great interest. It is a matter of regret that we are 

 not informed as to the natuie of the virus, which, 

 indeed, does not seem to have been discovered. It 

 is probable that Pasteur's studies in this direction 

 will lead to fruitful results. 



A large mmaber of observations are necessary in 

 order to establish the efficacy of Pasteur's treat- 

 ment of hydrophobia in human beings. His re- 

 sults certainly warrant a belief that, if tlie treat- 

 ment be begun soon after the reception of the 

 poison, this otherwise most hopeless and dreadful 

 disease can be prevented. Should this behef be- 

 come a proven fact, then Pasteur wiU merit the 

 gratitude of all mankind. 



THE PLAINS OF BRITISH AMERICA. 

 Striking contrasts present themselves to the 

 experienced "eye between the plains of British 

 America, through which the lately finished Cana- 

 dian Pacific railway has laid its tracks, and those 



crossed by any of the transcontinental lines in the 

 United States. In the first place, they are larger. 

 It is more than 1,000 miles froin where the forested 

 granites of Keewaydin dip under the Silurian 

 prairie-floor in the Red River valley to the first 

 escarpments of the Rocky Mountains. In Kansas it 

 is hardly half as far between the wooded region 

 and the foot-hills of Pike's Peak. 



Another feature is the prairie-like look of it all, 

 save certain far-western tracts. The grass is 

 dense and long, flowering herbage is profuse. 

 West of the South Saskatchewan this gives place 

 to a greater, more ' plains ' like scantiness of vege- 

 tation, to be sure, but nowhere is the bareness 

 and aridity of the southern plains equalled. 



This is due to the greater moisture in earth and 

 air, and to the extraordinary fertility of the soil ; 

 Manitoba producing an average of 21^ to 22 bush- 

 els of wheat to the acre, or 4 to 5 bushels in excess 

 of the average of any other similar space on the 

 continent. The soil is coal-black, and declares its 

 richness at first sight. Dr. Robert Bell, of the 

 Canadian geological survey, discussed the causes 

 of this fertility before the Canadian royal society, 

 May 23, 1883. He pointed out that the materials 

 were the best possible, having been derived from 

 the glacial drift of the north, mingling sand and 

 gravel with the cretaceous marls spread over all 

 British America. Having this favorable constitu- 

 tion. Dr. Bell assigns to the moles the chief agency 

 in the formation of the thick top-layer of vege- 

 table mould which is now the joy of the farmer. 

 In the Assiniboine valley the moles have thrown 

 up almost every foot of the soil into hummocks, 

 each containing a large shovelful of earth, and 

 burying completely the grass and vegetation over 

 a space a foot or more square. The vegetable 

 matter thus buried decays, and becomes incorpo- 

 rated with the soil; so that the process is analogous 

 to ploughing under the soil. This work of the moles 

 not only enriches, but refines the soil. In making 

 their burrows, they select the finer material and 

 cast it up to the surface, leaving behind the 

 coarser. The effect of this is similar to that 

 alleged by Darwin of the earthworms (which do 

 not exist in the north-west territories), since, in the 

 course of time, all the stones are buried. Their 

 labor is supplemented by that of the gophers, 

 spermophiles, and badgers, the last named digging 

 deeply, and heaving up large quantities of gravelly 

 subsoil, which the moles work into and improve, 

 while all bury much vegetable rubbish as nests 

 and food. This beneficent animal agency nearly 

 ceases, however, when the elevated hard and 

 stony 'third steppe,' called the Grand Coteau du 

 Missouri, is reached, and when the mountains are 

 approached, where the soil is clayey. 



