THE AOBICULTURAL JOUENAL. 



99 



The Dew has long been couaiderod to 

 possess some influence in the causation of 

 this disease. Exposure of animals during 

 the hours of dew precipitation is generally 

 looked upon as a dangerous proceeding 

 during the sickly season. We are told 

 to avoid exposure of the animal " while 

 the dew is on the ground." The exclu- 

 sion of dew by closing all doors and nail- 

 ing sacking over the windows has often 

 been adopted with success. Troughs and 

 drinking vessels have been covered with 

 a similar object. The above precautions 

 are held by many to be unnecessary 

 during rainy weather, when, of course, no 

 dew is precipitated. Heavy falls of dew 

 are particularly to be avoided. A hazy 

 misty morning of early autumn at the 

 close of the rainy season with low-lying 

 mists or fogs is reputed as dangerous 

 until such appearances have been dissi- 

 pated by the sun. 



Such popular ideas as above, connected 

 with the dew and the dew fall, have a 

 significance when it is remembered that 

 the period of greatest activity of the 

 mosquito family is about an hour before 

 sundown, and two hours after and two 

 hours before daybreak, and an hour after 

 sunrise. These periods, therefore, are 

 closely corresponding with the hours of 

 dew precipitation. This idea is somewhat 

 strengthened when one finds some 

 meteorological authorities asserting the 

 existence of two chief precipitations of 

 dew during the twenty-four hours (termed 

 by the French meteorologists the rosein 

 and the serrein) these two pi-ecipitations 

 taking place about sunrise and sunset, 

 and, therefore, corresponding closely with 

 the ascertained periods of greatest activity 

 of the mosquito. 



Remembering this fact it was with in- 

 terest that I heard the testimony of an old 

 Natal Colonist, who narrated to me an ex- 

 perience he had met with when travelling 

 in the Transvaal many years ago. Happen- 

 ing about sundown to find himself belated, 

 he turned aside for the night to a Dutch 

 homestead, but, it being the height of the 

 sickly season, he was somewhat concerned 

 at the prospect of leaving his horse, a valu- 

 able one, in strange quarters. On express- 

 ing this fear to his host he was told that 

 he need have no fear if he tied his horse 

 up in a shed for an hour or two after 

 sundown, and then knee-haltered it and 

 allow it to graze, being careful to tie it up 



again well before the sun rose, and so to 

 keep it tied up, if necessary, until the 

 sun was fairly up. This plan, the iiarrator 

 was told, had l)een followed for yeai's 

 with unvarying success by his host, who 

 had til lis i iijoyed an immunity in which 

 his ni'igli hours had not participated. 



While there may be considerable truth 

 in the experience, it would occur to people 

 that mosquitos are often troublesome 

 throughout the whole night, but it must 

 be remembered that different species con- 

 form to different halnts of life and hours 

 of activity, and that as many species of 

 mosquitos undoubtedly exist in South 

 Africa we are not justified in discounting 

 entirely such evidences, neither can we be 

 dogmatic upon a subject about which our 

 knowledge is at present to a great degree 

 mere speculation and conjecture. 



Such experiences, if those possessing 

 them will take the trouble to record them, 

 may become of considerable value in the 

 difficult work of the investigation 

 of this disease, and I again cordially 

 invite the ideas and theories of those 

 readers of the AgricultuialJoumal whose 

 experience leads them to the formation of 

 an opinion in any direction. 



The closing of stable doorsand windows 

 would l)e as effective in excluding winged 

 insects as dew. The covering of water- 

 troughs would possibly prevent the vicin- 

 ity being infested greatly by mosquitos. 

 That these insects do not fly during rain 

 and are numerous towards the autumn 

 after the rains, is a matter of evei-yday 

 observation, while dampness of grass and 

 humidity of atmosphere seem conditions 

 directly favouring mosquito activity. Thus 

 it is seen that the dew against which we 

 have so sedulously guarded may possibly 

 yet prove the truth of its harmless and 

 poetic character, and be blameable only in 

 so far as it permits nocturnal insectsi,to be 

 its constant companions and close associ- 

 ates. 



{To be continued).) 



The enormous yields of milk from certain 

 breeds of ows in the showyards are often 

 quoted, but usually nothing is said as to the 

 quantity and quality of the food consumed. A 

 dairy cow is practically a machine for convert- 

 ing the food she consumes into milk. The 

 American Agriculturist states that the Holstein 

 cow, Rosa Bonheur 5th, which held the world's 

 record, having produced 10l].751bs. of milk in 

 one day and 726.25lbs. in a week, ate daily 1141bs. 

 silage, 121b8. cornmeal, Olbs. oatmeal, 3ibs. bran, 

 yibs. oilmeal, and 27lbs. of roots. 



