Quinine and Fluorescence 173 



desirous of making his way, if possible, across the continent. 

 The speaker had also received a letter from Dr. Livingstone, 

 who was fitting out, at Bombay, his expedition for African 

 ^exploration. 1 



Dr. Bence Jones gave some results of experiments on the 

 rapidity of the absorption of quinine by various parts of 

 the body. These had also proved the existence in it of a 

 fluorescent principle. This Helmholtz had already noticed 

 (in 1853), when he observed that the retina of a man, eighteen 

 hours after death, was still fluorescent, though less so than 

 paper or linen, and more than porcelain, while in 1859 

 Tetschenow had shown the fluorescence of the lens in rabbits 

 and men to be very strong, exactly resembling, though not 

 quite so strong as, that of quinine, with which in optical 

 respects it agreed. It would be very desirable to isolate, 

 if possible, this fluorescent substance. 



Dr. Playfair gave an account of the conclusions arrived at 

 by the Commission for investigating the Cattle Plague. 

 The disease was undoubtedly contagious and very subtle. 

 Inoculation twelve or thirteen times in succession reduced 

 the mortality to about 14 per cent., but as yet no curative 

 appeared to have been discovered. He also stated that at 

 Madras, when smallpox virus had been mixed with five times 

 its weight of milk, no serious symptoms usually only a 

 single pustule were observed in 100 children inoculated. 



Dec. 2ist, I7oth meeting. Mr. Sylvester gave an account 

 of some movements of a planetary body about a centre of 

 force which had been described in his ' Astronomical Pro- 

 lusions/ published in the Philosophical Magazine for 

 January 1868. 



Colonel Sykes mentioned some exceptionally high readings 

 of the barometer in the current month. At his house in 

 Albion Street, Hyde Park, about 100 feet above mean-tide 

 level, his sympiezometer had recorded 30-9 on the loth 

 (at 10 a.m.), 30-8 on the I3th, the same on the iyth (at 

 3 p.m.), and 30-4 on the 2ist (at 10 a.m.) ; the thermometer 



1 That on which, after leaving Zanzibar in 1866, he discovered Lake 

 Bangweolo, was met by Stanley at Ujiji, and died on May ist, 1873. 



