OBITUARY. 



FRANCIS ORPEN MORRIS, M.A. 

 Born March 25, 1810. Died February 16, 1893. 



BRITISH Naturalists will learn with regret of the death of the 

 Rev. F. O. Morris, which took place at his residence, the 

 Rectory, Nunburnholme, Yorkshire, on February 16. Of those 

 •devoting themselves to the spread of an interest in Natural History 

 pursuits among the unlearned, Mr. Morris had long been a con- 

 spicuous figure ; and his success was gained both by the charm of 

 his personal enthusiasm and by the numerous, well-illustrated 

 popular writings which enabled him to reach a wider circle. His 

 best known and most valuable works are his " Histories" of British 

 Birds, their nests and eggs, and of British Butterflies and Moths, 

 the publication of the first commencing in 1851. The new school 

 of Biology inaugurated by Darwin and Wallace, unfortunately, never 

 found favour with Mr. Morris, and his long series of miscellaneous 

 writings antagonistic to this school began with a small volume on 

 "The Difficulties of Darwinism," published in 1870. 



CORRESPONDENCE. 



A Hypothetical Explanation of the Results of Inoculation. 



Mr. Bulman sets forth (Natural Science, vol. ii., pp. 100-109) ttie arguments 

 for and against two theories — the " E.xhaustion Theory " and the "Antidote Theory." 

 Another e.xplanation has been familiar to me for some time and to this he has not 

 referred ; I greatly regret that I am unable to say where I got it from, but I 

 rather fancy some part of it was " evolved out of the depths " of my own " inner 

 consciousness." 



It is as follows : — 



The attenuation of the virus by cultivation under conditions unfavourable to 

 the microbe's very rapid multiplication amounts to an artificial selection, the too- 

 rapidly-multiplying stocks being exterminated by overcrowding and the poisonous 

 effects of their own products. After several cultures, each raised from the survivors 

 of the preceding ones, an " attenuated virus " is obtained, i.e., a pure culture of those 

 stocks whose rate of multiplication is low. 



The selection may, however, act in some other way — the net result being that the 

 final culture consists of those stocks which, however they may behave on gelatine or 

 boiled potatoes or in chicken-broth or the blood of living apes or guinea pigs, are 



