194 



TUE AGBICULTUBAL JOJJBNAL^ 



Careful miscroscopical examination up 

 to the present has, however, failed to es- 

 tablish the probability of such a theory, or 

 satisfy the subsequent difficulties ^ of 

 transmission and indehnite reproduction 

 in an animal host. 



The nomenclature of the disease 

 (Oedema Mycosis) suggested recently by a 

 South African investigator is therefore 

 possibly inapt, and certainly premature, 

 inasmuch as other careful workers have 

 failed to demonstrate any degree of 

 mycosis or mould-invasion in post- 

 mortem examinations. 



That no intlanniiatory lesions are dis- 

 coverable in the lungs would seem to 

 point to a morbid process in which the 

 lung tissue played a passive or mechani- 

 cal part rather than being the seat of a 

 primary infection and development. 



That organisms of small size would bo 

 capable of easy dissemination through the 

 air is comprehensible, but it is not so easy 

 to see why such dissemination should 



take place" at a time when the air is 

 laden with moisture from the depositing 

 dew, and apparently at such time only, 

 for moisture tends to prevent the diffusion 

 of fine particulate matter through the 

 air. 



Points of resemblance exist between 

 Horsesickness and Kinderpest, notably in 

 the affection of the lachrymal mucous 

 membrane and in gastric symptoms, 

 which would tend to tlie classification of 

 the former as a catarrhal disease capable 

 probably of dissemination by the air. 

 Practical experience, however, disproves 

 the fact that any great degree of infec- 

 tivity exists, as animals stal^led closely on 

 either side of a case of the disease rarely 

 contract the disease. 



Experiment alone will be capable of 

 clearing up this obscure theory as to 

 whether the cause of Horsesickness is due 

 to respiratory infection. 



(To he continued.) 



Rain-making. 



By G. H. 



IN the last number of the Journal there 

 is, under the above heading, an 

 article dealing with rain-making experi- 

 ments in Australia with the "Stiger 

 Vortex." A full description of lliis 

 system was given in an English maga- 

 zine, and showed that the vortex is 

 created by means of gunpoAvdcr rxphjded 

 through a funnel directed at the clouds. 

 It is used, however, in Italy and in Hun- 

 gary, to prevent the foi'uiation of liail, 

 and one would suppose, tliei'i'fore, that its 

 effect would be rather to dissipate than 

 to condense. At any rate, your article 

 admits that Lord Kelvin and Professor 

 Boys do not seem to consider the fittem])t 

 to produce rain by its means as likely to 

 be successful, though the Australian 

 writer quoted is hopeful that some way 

 may be found to condense the heavy 

 L-\^)uds that are naturally carried by the 

 air currents to the warm atmosphere of 

 the desert. The latter seems to be as- 



Davjbs. 



tonished to find that these clouds do not 

 then condense, but, surely, he sliould be 

 more astonished if they did. The sur- 

 face of a bare country is a good conductor 

 of heat, and warms the air above it so as 

 to speedily rarity the heaviest clouds, 

 while the cold air beyond rushes into the 

 less densely filled space held by the heated 

 air, and blows away the now attenuated 

 vapours. It is, of course, possible, as he 

 suggests, that science may find some 

 means of condensing clouds over a super- 

 heated country, but it does not seem very 

 likely. The obvious course is to cool 

 the surface of the soil, and thus let the 

 air above become cold enough to con- 

 dense the clouds, but how mechanical 

 science is to do this is not even faintl}^ 

 suggested. It is, however, wonderful 

 wliat attraction is found in complicated 

 methods, while well-tried, simple, and 

 absolutely certain remedies lie plain 

 around us. How does Nature not merely 



