572 
tunnels for themselves, when still more disastrous results 
may accrue. The abrasion and destruction of surfaces and 
cells and the opening up of abnormal communications are 
not, it is urged, of such serious importance of them- 
selves; it is rather the secondary results from such 
lesions that are to be feared, such, for example, as the 
admission of bacteria from the alimentary canal into the 
blood and tissues. For it is held by many that the normal 
mucous surface is impenetrable by bacteria, and the germs 
of cholera and typhoid depend to some extent upon 
diminished resistance, functional or structural, for their 
entrance into the tissues. 
No one, for instance, doubts that Eberth’s bacillus is 
the active agent of typhoid, but there is strong reason to 
believe that before it can give rise to the disease there must 
be lesion of the intestinal mucous membrane. The very 
fact that out of numbers who drink contaminated water 
but comparatively few are infected is strong confirmation 
of this. 
Parasites are likewise the inducing cause of changes 
which lead to multiplication, or proliferation, of cells and 
tissue, this being the case with both protozoa and bacteria. 
The most common morphological change in the host 
is, perhaps, the development of a cyst round the parasite. 
An example of this is afforded in the case of pearls. In 
the Ceylon pearl-oyster the production of the best pearls 
is due to one particular cestode larva which passes part 
of its existence in the mollusc itself. 
On the other hand, the attempt to attribute cancerous 
and other abnormal growths to the action of parasites 
does not appear ta be supported by the available facts. 
As regards such proliferation of tissues as is undoubtedly 
due to parasitic action, Prof. Ward advances the hypo- 
thesis that this may be largely owing to poison generated 
by the intruder. An inert body, like a grain of sand, will 
not give rise to the formation of a cyst, or at all events 
to the proliferation of tissue, and it is probable that pearls 
cannot be produced by such means. Parasitic bodies, on 
the other hand, feed and excrete, and nothing is more 
probable than that the excreta are toxic. 
This, however, is not all, for the supply of nutriment to 
the parasites—nutriment frequently consumed in a wasteful 
manner—inflicts a severe strain on the host in a large 
number of instances. The drain on the resources of the 
latter is, indeed, practically three-fold, owing to the rapid 
growth of the parasite itself, the production by the latter 
of a large amount of reserve material (glycogen), and the 
great reproductive activity of the unbidden guest. 
A curious phase of parasitic infection is the frequent 
loss of reproductive power in the host, due in some 
instances to destruction of the genital organs themselves, 
but in others to secondary influences. The tendency for 
one sex to acquire the sexual characteristics of the other 
is a marked feature in this parasitic castration. 
The destruction of tissue by parasites, as in the case 
of that of the liver by the liver-fluke, although in one 
sense a mechanical injury, is really more than this. As 
the substance removed by the liver-fluke is replaced by 
connective tissue,.a most important organ of the body 
becomes to a greater or less degree degenerate. 
Among the physiological effects of parasitic infection, 
none is more remarkable than the power possessed by 
species living upon blood of secreting a substance which 
prevents the coagulation of that fluid. In regard to what 
has been stated above as to the development of toxic 
elements by parasites, the hmosporidia of malaria 
undergo development in the red blood-corpuscles, and when 
they break up into spores the corpuscles are destroyed, with 
the probable discharge of poison into the blood. As many 
corpuscles break up at once, the effects are serious. The 
trypanosomes of sleeping sickness probably have a very 
similar physiological effect. The existence of a toxic prin- 
ciple affords also the most satisfactory explanation of the 
phenomena of the progressive, pernicious anemia present 
in some cases of bothriocephalid infection. Anzmic con- 
ditions are also produced by direct blood-suckers, such as 
leeches and fish-lice. There remain, however, other forms 
of anzmia, such as that due to infection by the fish- 
tapeworm Dibothriocephalus latus, the physiology of which 
cannot at present be satisfactorily explained. 
NO. 1954, VOL. 75] 
NALRORE 
[APRIL 11, 1907 
THE BELGIAN INTERNATIONAL BALLOON 
SERVICE. : 
HE investigation of the higher regions of the atmo- 
sphere by means of unmanned balloons, which has 
been carried on by some countries for several years, 
generally on the first Thursday in each month, has already 
revealed some important facts, among which may be 
mentioned the inversion of temperature at various heights 
and the determination of the direction of the flow of the 
upper air-currents over land and sea. The success hitherto 
attained well repays the expenditure of time and money 
incurred, and gives good reason for hoping that the study 
of aggregate results may lead to the ultimate solution of 
the problem of the general circulation of the atmosphere. 
At the instigation of the aéronautical conference held in 
St. Petersburg in August, 1904, the Belgian Meteorological 
Service has taken part in this important work since the 
end of March, 1906, and M. Lancaster has sent us pre- 
liminary notes of the results of the monthly ascents from 
Uccle between April, 1906, and February, 1907, published 
in Ciel et Terre, and in a note to the Belgian Academy 
in November, 1906. We have previously referred to the 
ascents in April and May, but include the data in the 
following general summary. 
The balloons are of india-rubber, coupled in tandem, 
having generally diameters of 1900 mm. and 1350 mm. 
respectively, and are inflated with hydrogen gas. The 
meteorograph is made by Bosch, of Strassburg, and con- 
sists of barometer (Bourdon tube), two metallic thermo- 
meters (Hergesell and Teisserenc de Bort’s models), and 
hair hygrometer. A full description of the apparatus is 
given in Ciel et Terre for May, 1906. In this paper the 
values quoted are from Dr. Hergesell’s thermometer. The 
starting place of the balloons at Uccle is 100 metres above 
sea-level, and the ascents were made from about 7h. to 
7h. 30m. a.m. Greenwich time. 
General Results of the Ascents. 
Tempera- Lowest Direction 
Date | Wind ture at |temperature Height in which 
starting recorded | balloons fell 
1906 OG, AG, metres 
April 5... SE 1°9 —57'2 13,500 Sushila. 
May 3... | S.S.W. ERE — 62°6 10,160 | E.N-E. 
June 7 een a Nek 13°7 —65°7 11,460 | S.S.W. 
July 5...| N.E. 16°6 —58'0 9,829 | Ss. 
Jif Pen, || Sash! 22°0 —59'8 13,704 E. 
Oct aves eGalm 119 —65°3 11,524 Sa. 
Nov. 8... | N.N.E. 9°0 60°8 10,504 | N.W. 
IDS Osta || SUSE NG o'8 —51°6 9,168 | S.S.W. 
Jan. 14... |W.S.W. 52 — 702) |" 12,;360 |e sone. 
[ 15,346 | 
183) 95 Y/saa|| shia) Oy - 62°0 | and S.S.E. 
| (17,073 
The following details, not included in the above table, 
are of interest :-— 
April.—An inversion occurred between 14,000 metres and 
15,000 metres. 
May.—A large inversion occurred above 10,160 metres; 
at the maximum height, 16,970 metres, the temperature 
had risen to —42°-0 C. Humidity fell to 18 per cent. at 
10,330 metres, during the descent. 
June.—Above 11,460 metres an inversion occurred up 
to the greatest height, 15,690 metres, where the thermo- 
meter read —54°-5 C. Humidity, 22 per cent., at 2520 
metres. 
July.—Inversion occurred between 9800 metres and the 
maximum height, 15,682 metres, where the thermometer 
read —50°-0 C.; humidity, 19 per cent. 
August.—At the maximum height, 18,835 metres, the 
temperature was —50°-3 C.; between 13,800 metres and 
18,000 metres there was an inversion in a layer about 
4000 metres in depth. we 
September.—The meteorograph was broken by collision 
with buildings at starting. 
