19G THE JOURNAL OF BOTAXY 



The reaction of the thalhis with potassium hydrate is, as in the 

 species, a purplish red colour due to the presence of salazinic acid 

 (Lettau in Hedwicfia, Iv. 25, 1914). On applying the reagent to 

 the lichen, before the relation to the substratum is disturbed, a 

 rapidly developed purplish red colour becomes evident ; but if a small 

 portion of the thallus on the under side of the epidermis of the ivy is 

 scraped off neither the hyphse nor the algal cells show the deep stain ; 

 they are practically not changed at all. It is the periderm cells, 

 through which the' hyphte have ramified, that become so markedly 

 coloured and show so readily through the thallus above. The same 

 may be said of the dead phellogen layers of the oak bark, it is the 

 contents of these cells that exhibit the dark purple reaction with 

 ]K)tassium hydrate. As to the thiekish granular thallus, so abund- 

 antly developed on the exposed surface of the outer bark, the hyplu« 

 do not stain with the reagent and many of the algal cells are un- 

 alfected, but in some, where the green colouring matter has become 

 yellow or colourless, the contents show a pink reaction tinge. The 

 algal cells are the normal Protococcus green shells which are some- 

 times stained yellow. The hyphse are remarkably wide, being from 

 2 to 3 in. in diameter. — Robeet Paulsois^. 



KEVIEWS. 



Scirnce and tlie Nation : Essays by Cambridge Graduates with an 

 Introduction b}^ the Right Hon. Lord Moultox, K.C.13., 

 F.ii.S. Edited by A. C. Seward, F.R.S., Master of Downing 

 College. Cambridge University Press, 1917. Pp. xxii + 328. 

 Price OS. net. 

 Lord Moulton prefaces this valuable volume of essays with a 

 weighty indictment of our national notion of education. " It has 

 been fashionable," he says, " for the well-to-do to choose for their 

 children an education devoid of Science and indeed devoid of con- 

 tinuous intellectual effort .... it was considered no shame that a man 

 should leave his University not only ignorant of Modern Languages 

 and Science but also unprovided with any economical or commercial 

 training that could lie of value to him in practical life. This example 

 has been followed by other classes of the community who have 

 naturally accepted the standards of education adopted by the Avealthier 

 classes as being the best, and thus much of the best human material 

 that England produces has been set to its work in life without any 

 si)ecial prei)ai'ation for the task before it." As Sir Arthur Evans put 

 tiie matter in his address to the British Association at Newcastle, 

 English opinion is not so much indilferent as actually hostile to 

 education ; and the thirteen Cambridge Professors whose essays are 

 here marshalled by Professor Seward have set out to demonstrate to 

 a nation of philistines the practical value of pure science. It is, 

 }M3rhaps, appropriate that such a volume should appear under the aegis 

 of the re})resentative of so purely scientific a study as paheo-botany ; 

 but, whether the writer be chemist, metallurgist, mathematician, 

 forester, geologist, agriculturist or physician, the main thesis is the 

 .same throughout, viz. that much of the supposed distinction between 



