189 



Tn some of the fruits of the papaw the seeds numbe r five, in others 

 prodigal nature supplies over five hundred, apparently only a few of 

 these seeds are fertile. When a native desires a single tree, be buries 

 two or three such fruits in the ground, and at most two or three plants 

 are the result After continued experiment it was found that seeds 

 taken from the central portion of the largest and finest fruits were the 

 most likely to be fertile, and would give more encouraging results 

 The proper adjustment of the sexes in trop'cal soil is difficult and 

 exasperating. 



The papaw is much like the nutmeg in its vagaries of sex relation. 

 It is grnerally agreed that for fertilization one male to ten female 

 plants is the proper ratio, but until the trees arrive at the blossoming 

 stage (five years in the case of the nutmeg) the male cannot be dit-tin- 

 guisbed from the female. Oue can imagine the dismay of the culti- 

 vator who finds at the end of all his toil and waiting that he has a 

 plantation of male non-fruit-beaiing instead of the coveted female, or 

 fruit-bearing plants. I have records of numerous instances where 

 acres of ground were planted with thousands of papaw plants in which 

 the males were in the majority of over fifteen to one. 



This constantly recurring disproportion of the sexes suggests that 

 in cultivation we were so changing environment as to cause a perver- 

 sion of the sexes, resulting in a race of non-fruit bearers. 



Methods of artificial fertilization and budding, such as is followed 

 in the propagation of melons and oranges, are now in the experimental 

 stage. 



CONTAGIOUS SKIN DISEASES OF THE HORSE.* 



By Dr. Theiler. 



Prevalence of Skin Diseases. 



One of the most striking results of the importation of a large num- 

 ber of horses from foreign countries has been the appearjince of skin 

 diseases, hardly ever met with in this country previous to the war. 



ISkin diseases have spread in an alarming way, and are now very 

 common. They are very troublesome and sometimes hard to cure, 

 and have caused the death of many valuable animals, losses which can 

 only be attributed to a weakening of the system and the emaciation of 

 the subjects. 



Mange. 



These diseases are commonly known by the common name of Mange ; 

 they are not always the actual Mange, but at the present time it is 

 certainly the most prevalent disease. 



The expression " mange" includes all skin diseases caused by a small 

 parasite, belonging to the class of Arachnoidea related very closely to 

 the tick family, one well known to every inhabitant of South Africa. 



* From the Transvaal Agricultural Journal, Vol. I. No. 3. April 1903. 



