146 TRYPANOSOMIASES OF RHODESIA. 



"direct," and that only a small' percentage of flies are infective. 

 This limits the danger, but, given a reservoir of virus, the number 

 of infectible Glossina iiiorsita>is in a " belt " must still be very 

 great. 



Bagshavve points out that certain climatic atmospheric or 

 telluric conditions may be necessary before the Glossina mor- 

 sitaiis can assume the role of Glossina palpalis. Neave, as the 

 result of a tour through the infected area, drew attention to the 

 strange occurrence of cases in certain huts in certain villages — 

 these usually the bachelor's huts, which he pointed out were 

 the dirtiest and were occupied by visitors to the kraal. This 

 feature does not point to infection by Glossina uiors'itans, but 

 rather to some insect inhabitant of diuman dwelling-places, such 

 as the 0)')iithodonis, floor-maggot, flea, bed-bug, etc. Dr. 

 MacKnight has tried to transmit the disease from a native patient 

 to healthy dogs by the bite of Oniitlwdorus nioubafa without 

 success, but Bagshawe points out that time was not allowed for 

 a cyclical development in the ticks to be completed. 



I have also been experimenting with the same species of 

 tick, in the adult and intermediate stages, both by interrupted 

 feeding and by allowing long intervals to elapse between the 

 feeds, with interesting results which cannot yet be published. 

 At any rate, until the actual transmitter is proved, it is improper 

 to loosely incriminate any insect, especially one so widely dis- 

 seminated as Glossina nwrsitans. The fear caused by unfounded 

 statements may seriously and unfairly handicap the progress and 

 development of this country. 



Although I have dealt but superficially with my subject, I 

 have drawn attention to the many branches of the question re- 

 quiring scientific research and investigation. For those who are 

 less interested in the scientific than in the economic aspect of 

 the subject, I would emphasise the necessity for well-staft'ed and 

 adequately-equipped laboratories on the spot, where these 

 diseases can be studied in natural conditions and with greater 

 hope of success. 



TRANSACTIONS OF SOCIETIES. 



Cape Chemical Society. — Friday, August 25th: Prof. B. de St. J. 

 van der Riet, M.A., Ph.D., President, in the chair. — " The utiHsation of 

 lime shidge from acctj-lene generators "' : Prof. B. de St. J. van der 

 Biet. The sludge was being used at Stellenbosch for whitewashing as 

 well as for manurial purposes. It consisted chiefly of slaked lime with 

 calcium sulphide. For gardening it was necessary to get rid of the 

 latter. The sludge was allowed to settle in perforated tanks, the water 

 draining away and leaving a fairly stiff residue. IMixed with potash and 

 crushed bones the author had found it an effective fertiliser. — " No'.e 

 on an insect wax from Stellenbosch": Prof. B. de St. J. van der Riet. 

 The wax occurred on myrtles, and was produced by a coccus. It was 

 freely comlnistible and, when softened by heat, was capable of bein;? 

 drawn out into long threads. The insects yielded about 30% of v/ax. — 



