August ii, 192 i] 



NATURE 



75, 



with in adults. He argues from all this that in- 

 dividuals with occult tuberculosis- — the so-called 

 healthy carriers of tubercle bacilli — are largely 

 responsible for the spread of tuberculosis, not only 

 amongst aboriginal and hitherto isolated peoples, 

 but also amongst infants. He claims that this 

 recently acquired knowledge of an unexpected 

 danger makes the organisation of social defence 

 against tuberculosis more difficult than when pro- 

 phylaxis had to be based only on the education 

 and isolation of phthisical patients, though he 

 concedes that these are the principal dis- 

 seminators of the disease. New peoples and 

 infants should, wherever possible, be protected 

 through a system of detection based both upon 

 the judicious use of tuberculin tests and upon 

 clinical examinations of the glandular system 

 mainly by means of radioscopy. 



It was interesting to find that Dr. Eric 

 Pritchard, working along these lines during a 

 period of ten years, had passed through his 

 hands some thirty children who, by a process of 

 injection with Koch's original tuberculin extend- 

 ing over five months, first in minute doses, to 

 which they reacted, gradually increased up to 

 I mg., to which the reaction was no more 

 marked, could be immunised against any 

 infection they were likely to be exposed to in the 

 course of their lives. No accident such as might 

 have been anticipated had occurred, and he was 

 very hopeful that they had passed over that 

 susceptible period of which Prof. Calmette had 

 spoken. 



It was felt by some who beard Prof. Calmette 

 that his hypothesis, unless more fully explained, 

 might lead to great misconception on the 

 part of the public and be advanced as a 

 reasonable excuse for inaction. If any apparently 

 healthy person may be a " carrier " — and all may be 

 infected in infancy — what good are elaborate pre- 

 cautions against tuberculous infection? The vari- 

 ous public authorities might feel justified (and 

 some might wish this) to sit with folded arms and 

 tightly buttoned pockets. Later Prof. Calmette 

 made it clear that his reference was only to those 

 who had not hitherto been brought into contact 

 with tuberculous patients, such as native races and 



infants, and that in civilised tuberculous com- 

 munities other factors, surroundings, conditions 

 of life, sources of infection, etc., must all receive 

 due consideration. It was insisted that much 

 information on these points had already been 

 accumulated, and that the time had undoubtedly 

 arrived when the aid of legislation should be 

 called in for the prevention of tuberculosis. 

 Two great sources of infection, human and bovine 

 — expectorations from the former, and milk from 

 the latter — containing massive doses of tubercle 

 bacilli, must still be dealt with, and dealt with 

 effectively. No measure conducing to the removal 

 of mass infection should be neglected. Panic or 

 phthisiophobia may well be discouraged when we 

 learn from Sir George Newman that in seventy- 

 three years, since 1847, when the death-rate from 

 tuberculosis was 3189 persons per million living, 

 there has been a fall of 74 per cent., the standard 

 death-rate from phthisis in this country in 1920 

 being 842 per million living. In other countries 

 the decline, though not so marked, is still very 

 substantial. 



One feature Avas very prominent throughout the 

 whole of the discussions. Although the search for 

 prophylactic aids should not be discontinued, it 

 must be recognised that the processes involved 

 in tuberculosis are of a type different from those 

 involved in most of the acute infective diseases, 

 such as typhoid, plague, and the like, and, accept- 

 ing this, we must follow Sir George Newman in 

 his advice that " there is no beaten track in the 

 further conquest of tuberculosis"; "the healthy 

 child and the adult must be protected from 

 massive, frequent, and prolonged infection"; "the 

 powers of resistance of the patient must be forti- 

 fied." "Freedom of thought, wide and deep re- 

 search, and mobility of action will be necessary. 

 Of much are we still in doubt, but of three things 

 we may be certain. Only by surveying the com-, 

 plex problem, as a whole, in the spirit of pre- 

 ventive medicine, and co-ordinating the respective 

 factors concerned, only by thorough, construc- 

 tive, and intensive practice of our principles and 

 by searching and finding the hidden secrets of 

 immunisation,- shall we at last conquer this 

 disease." 



The Progress of British Forestry. 



'T'HE First Annual Report of the Forestry Com- 

 -■- missioners (H.M. . Stationery Office, 192 1, 

 gd. net) deals with the period ended September 30, 

 1920, since which date a whole planting season 

 has intervened ; but a preliminary note gives in- 

 formation of the progress made to date. The 

 Forestry Commissioners are now in actual pos- 

 session of 103,100 acres of land, of which 

 68,100 acres are classed as plantable with timber 

 trees. The planting operations of the season 

 1920-21 have been successful, and the total area 

 of new plantations is now about 8000 acres, while 

 the stock of young trees in the nurseries is suffi- 

 NO. 2702, VOL. 107] 



cient to plant next season a largely increased 



area. 



The Report opens with a sketch of the history 

 of forestry in the United Kingdom, showing the 

 stages w^hich led to the passing of the Forestry 

 Act in 1919. State forestry is a new departure 

 in this country, and this part of the Report will 

 instruct the public in the significance of a national 

 forest policv. In the first period — ^that of destruc- 

 tion of the original forests, which lasted in some 

 districts up to 1750 — great clearances were made 

 for agriculture, sheep pasture, and the smelting of 

 iron-ore. In the next period — that of private 



