sheep-pox, epithelioma conlagiosum of birds, swine fever, rabies, cow-pox (vaccinia), molluscum conlagiosum of man, equine in- fectious pernicious anaemia, canine distemper, " blue tongue " of sheep, dengue fever, papataci or sand-fly fever, smallpox, trachoma, poliomyelitis, scarlatina, measles, typhus fever, and trench fever. There are many observations indicating that the primary cause of pandemic influenza may be a filterable virus.
Two filterable viruses fall into a class apart. They are dis- tinguished from the others in that they do not seem to produce disease directly by their poisonous activities but rather to stimu- late certain cells of the body in the neighbourhood of their in- oculation to excessive and anarchical development. The injection of these viruses into certain varieties of fowls leads to sarcomatous new-growths of great malignity. In the one case it is a pure sar- coma, in the other a mixed tumour, an osteo-chondro sarcoma. These malignant tumours spread not only by proliferation at the point of origin but some of the cells of which they are composed, boring their way into blood vessels and lymphatics, are carried all over the body, giving rise to similar tumours in internal organs. The metastases as well as the primary tumours contain the virus, and if extracted with water and filtered through a bacterial filter, whereby all the cells of which the tumour is composed are held back, the filtrate may be dried and powdered and the powder retains its original property of exciting the formation of these malignant tumours in suitable animals into which it is injected. The experiment may be repeated indefinitely through generations of young chicks, showing that the virus propagates itself and appears to live in some sort of symbiotic manner with the particular cells it excites to inordinate development.
It frequently happens that one observer succeeds in passing a particular virus through a filter, whilst another fails. When the particles of a virus are of the same order of magnitude as the crevices of the filter this may well happen, as in any case the majority will be retained in the wall of the filter. Even when the size of the particles of virus are much less than that of the smaller pores, they are liable to be deposited upon the walls of the minute passages under the influence of surface action and the filtrate becomes thereby greatly reduced in concentration.
In addition to size, shape, and rigidity of particles, the conditions under which filtration is carried out, pressure, temperature and amount of liquid passed through the filter, exert an influence. With high pressure some may be forced through which would otherwise be obstructed. This is particularly the case when the particles are of unequal dimensions in two planes. The nature and reaction of the liquid in which the virus is suspended is also of importance. If suspended in a colloidal solution such as blood serum or a slimy emulsion of nerve tissue, high dilution is necessary for the colloidal particles of the solution or emulsion are themselves deposited on the walls of the pores and rapidly reduce the permeability of the filter. Reaction plays a part by modifying the electric charge on the particles and thereby facilitating or hindering their aggregation and deposition on the surface of the filter pores which is also charged.
The fact that a virus, under certain circumstances, traverses a bacterial filter, does not tell us any more as to its nature than that it is very small, or at least very thin, and of the order of o-l to 0-2 /* or less in its smallest diameter. It is not necessary to assume a contagmm fliiidum in the case of those viruses which are outside the range of visibility under the best optical arrangements at present available. The particulate nature of the infective agent of rabies, fowl plague, variola and vaccinia, is indicated by the fact that the upper layer of a liquid containing them may be deprived of infec- tivity by prolonged subjection to a powerful centrifugal force.
Little is known about most of these filterable viruses. They ap- pear to be of various natures, and the only property common to them is minuteness. The parasite responsible for yellow fever is a small spirochaete, those occasioning bovine pleuro-pneumonia and human poliomyelitis are just on the margin of visibility and have been cultivated in artificial media. Some of them occur in the blood of the patient during the acute stage of the illness and are transported to a fresh host by the bite of blood-sucking insects. The infections of yellow fever and dengue are conveyed by the mosquito (Stegomyia fasciata). That of papataci fever is transmitted by the sandfly (Phlebotomus papatasu), and that of typhus and trench fevers by lice. In each case some days elapse before the insect is capable of handing on the infection, indicating that an interval for the mul- tiplication of the parasite is necessary. It is possible that a stage in the life-history of the parasite can only occur in the body of the insect host. Some filterable viruses, such as smallpox, cowpox, foot-and- mouth disease, and molluscum contagiosum give rise to superficial lesions, and are spread by contact; others occasion catarrh of the respiratory passages and are distributed by coughing and intimate contact, as in distemper, measles, scarlet fever and pleuro-pneumonia. In many cases the precise method of infection had still been undetermined in 1921. (C. J. M.*)
FINANCE (see 10.34). The continuous developments of national finance in the different countries of the world during 1910-21 are dealt with in articles under separate headings, where the relevant statistics in each case will be found (see ENGLISH FINANCE, and the sections on "finance" in the articles under country-headings, e.g. UNITED STATES, FRANCE, GERMANY, etc.). Under other headings also the mechanism of finance and the chief subjects of general financial-economic interest are further discussed, historically and statistically, on their own account. Thus the new developments of special moment arising in con- nexion with the market for securities are discussed under STOCK EXCHANGE, those affecting the money-market under MONEY- MARKET, questions of foreign exchange under EXCHANGES, FOREIGN, banking under BANKING (together with the article on the new FEDERAL RESERVE BANKING SYSTEM in the United States), and insurance in its various forms under INSURANCE. Similarly, reference may be made to the articles NATIONAL DEBT, GOLD, SILVER, WAR LOAN PUBLICITY CAMPAIGNS (Brit- ish), LIBERTY LOAN PUBLICITY CAMPAIGNS (American), DOLLAR SECURITIES MOBILIZATION (as part of British Government fi- nance during the war), SAVINGS MOVEMENT, INFLATION, PROFI- TEERING, INCOME-TAX, EXCESS PROFITS DUTY, COST OF LIVING, WAGES, PRICES, FOOD SUPPLY, RATIONING, CAPITALISM, COM- MUNISM, MARKETING, etc., for particular questions which have either loomed larger, or emerged as practically new problems, in the financial and commercial world. Incidentally, the finan- cial effects of the World War form an integral part of the history of every form of human activity during the period, and therefore receive appropriate consideration under numerous other head- ings where the subject-matter belongs to the sphere of business and economics.
It only remains here to gather up the threads of the general world-situation in finance, as it stood towards the close of 1921.
The end of the war had left the whole financial world in 1919 in a state of chaos. 1 Its conditions were comprehensively reviewed in 1920 at the International Financial Conference which, as arranged by the League of Nations in Feb., met at Brus- sels from Sept. 24 to Oct. 8. There were 86 representatives of
TABLE I. National Wealth, and Budget Revenue and Expenditure ' (in dollars)
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U.S.A. Australia United Kingdom . France .... Canada .... Germany 3
364 258 243 185 1 80 149
7-5 17 19
22
17 8
2
8
12
9
S
730
342
416
239
335
72
70 28
100
34 33 n
JO
S 24 '4
10
15
70 63
IOO
84
75 25
JO
/5 24 25 3i 35
Italy . . . .
no
H
13
88
12
14
25
28
Japan ....
30
6-5
22
76
8
IT
10
/?
1 Nothing is said here of Russia, which, economically and finan- cially, was in collapse, with its internal and external trade-relations completely paralyzed (see RUSSIA). It may be mentioned that, in 192 1 , a somewhat farcical turn was given to the hopeless depreciation of the ruble by an official exchange-rate of 133,000 rubles to the being " fixed ' by the Soviet government. Any other huge figure would have done as well! The progress of ruble inflation is shown by the following figures for the total issues in circulation (in million rubles) : Aug. 1914, 1,700; Jan. 1915, 3,215; Jan. 1916, 5,737; Jan. 1917, 9,225; Nov. 1917 (Kerensky), 18,917; Jan. 1919 (Bolshevist), 61,265; Jan. 1920, 225,216; Jan. 1921, 1,168,598; Jan. 1922 (est.), 2,000,000.
2 Pre-war figures in dollars at par of exchange: post-war at ex- change of Sept. 30 1920. 3 Reparations liability excluded.
