154 
NATURE 
DECEMBER 17, 1896 
the 15th, instead of on the morning of the 14th as expected: 
In 1879 I found the greatest density of the shower occurred 
some hours before its probable time, while in 1888 the best 
display came six hours later than I had been led to expect. 
Minor returns are, however, more difficult to determine as 
regards the exact period of maximum, and are likely to teach 
us little in this respect. The state of the sky, the altitude of 
the radiant, and the presence or absence of the moon have 
each an important effect on the visible aspect of a meteor 
shower, and render fair comparisons from year to year scarcely 
possible, the circumstances being rarely the same in two cases. 
The Leonids in 1896 were certainly more numerous, judging 
from the majority of the reports, than in an ordinary year, and 
no doubt a further increase in their strength will be apparent in 
1897, but the moon will then rather seriously interfere with observ- 
ation. Judging from the times of maxima observed in 1799, 
November 12 a.m., 1833 November 13 a.m., and 1866 Novem- 
ber 14 a.m., the maximum will occur before midnight in 1899 ; 
but we have a good prospect of observing the return of 1900 at 
about 3 a.m. November 15. As regards the next return in 1933, 
it will probably be well seen from the eastern parts of Europe, 
while that of 1934 seems likely to be witnessed from England on 
the morning of November 16. Too much confidence should not, 
however, be placed in these indications, as the shower has ex- 
hibited some irregularities in the past. Thus in 1867 it returned 
about two hours later than its computed time, while in 1868 it 
most unexpectedly proved quite a brilliant display about fifteen 
hours. after its time. W. F. DENNING. 
Bristol, December 10. 
Oyster Culture in Relation to Disease. 
In Dr. T. E. Thorpe’s paper in the issue of NATuRE for 
December 3, there are several erroneous statements which are 
not calculated to do good. He says that the ‘‘ Belgian and 
Dutch oysters. chiefly come to. Grimsby and Brightlingsea.” 
This is quite wrong, as the greatest quantity of Dutch oysters 
come to London, some go to Manchester, .Liverpool, and 
other large towns: Belgian oysters are nearly unknown in 
England. > 
Again, Dr. Thorpe says that the greatest number of oysters 
are eaten in September. This again is wrong. The greatest 
quantity of oysters are sold in the months of November, 
December, and January. 
Again, Dr. Thorpe says ‘‘ the value steadily increases up to 
December, and gradually diminishes month by month until it 
reaches the minimum in June and July.” This is not correct, as 
the better class of oysters do not come to market so late, and the 
price of good oysters is always maintained. 
Dr. Thorpe says, further, ‘‘the layings in the bed of the 
Colne, which presumably furnish the supply for the time- 
honoured ‘ Colchester Feast,’ are subjected to the comparatively 
concentrated effluent of Colchester sewage at low water, and to 
the additional pollution to which the river is subjected at 
Wyvenhoe and Rowhedge.” The oysters sent by the Colne 
Fishery Board to London and the continent, also those eaten 
at the ‘‘ feast,”’ are not fattened in the bed of the Colne, but in 
a_ creek lower down the river called the *‘ Pyfleet.” On page 
28 of Dr. Cartwright Wood’s report, reprinted from Zhe Britésh 
Medical Journal, he calls the Pyfleet oyster the standard oyster 
for purity. Dr. Cartwright Wood, on page 25, also says ‘‘ these 
experiments accordingly, as far as they go, tend strongly to 
confirm the view that in a state of nature the oyster might very 
rapidly get rid of the effects of contamination.” 
The Park, Flutton, Essex, December 7.  G. H. BAXTER. 
BEFORE your correspondent peremptorily asserts that certain 
statements are ‘‘ quite wrong,” it might be worth his while to 
ascertain that he was quite right in so doing. To begin with, 
he has evidently not read the Report to the Local Government 
Board ‘*On Oyster Culture in Relation to Disease,’ or he 
would have discovered that the statements to which he takes 
exception are made not on my authority, but on that of 
the Inspector of the Local Oyster Industries. On p. 24 of 
Dr. Bulstrode’s report, under the heading ‘‘ Oysters imported 
direct from abroad and consumed without being relaid in our 
waters,” it is stated that ‘‘large quantities are also imported 
NO. 1416, VOL. 55] 
from Holland, Belgium, and other countries. . . . lam informed 
by Mr. Mussun, of Liverpool, with whom I conferred at 
Cleethorpes, that the chief ports for the introduction of 
American oysters into this country are Liverpool and 
Southampton, and for North Sea oysters Grimsby and 
Brightlingsea.” 
It is not to be supposed that all the oysters imported into 
Grimsby are eaten there: no doubt they find their way ‘‘ to 
Manchester, Liverpool, and other large towns.” 
I stated, on the authority of Dr. Bulstrode, that in 1894 
27,747,000 oysters, of the value of 84,271/., were landed on the 
English and Welsh coasts by English dredges. Dr. Bulstrode 
also gives the following table (p. 4), showing how this number 
was distributed over the several coasts, together with the 
corresponding value of the oysters. 
Month. Oysters. Value. 
January 2,289,000 48437 
February 2,217,000 7846 
March 2,231,000 6838 
April 1,768,000 6050 
May 2,096,000 5497 
June 1,768,000 3948 
July 1,694,000 3967 
August 2,670,000 6909 
September 3,124,000 8054 
October 2,947,000 8585 
November 2,426,000 7493 
December 2,517,000 10,647 
27,747,000 £84,271 
This table shows that the greatest number of oysters are landed, 
and’ therefore presumably eaten in September, and that their 
value increases up to December, and then gradually diminishes 
month after month until it reaches a minimum in June or 
July. 
My remarks on the Colne oyster layings were based on the 
statements of Dr. Thorne Thorne (p. xii) and Dr. Bulstrode 
(p. 40). The latter gentleman, after mentioning the fattening 
grounds in the Pyfleet, which, of course, are distinct from the 
layings in the Colne, says : ‘* Provided, therefore, that all oysters, 
prior to consumption, are laid down for a sufficient period on the 
fattening grounds of the Pyfleet, there is probably no reason 
to suspect the wholesomeness of Colne Fishery oysters, but it 
seems to me very undesirable that oysters should be despatched 
from market direct from the bed of the River Colne.”* 
Ihave no desire to asperse unduly the character of the Colne 
oyster, of which, if I were an Essex man, and interested in 
its culture, I should be as jealous as Mr. Baxter apparently is. 
I can only hope, therefore, with Dr. Cartwright Wood, that 
when the Colne oyster finds itself at the sea-side, and ‘‘in a 
state of nature,” it not only ‘‘ might” but will “get rid of the 
effects of contamination,” and rapidly show itself ‘* the standard 
oyster for purity.’’ Still, on the whole, it is to be preferred that 
the oyster, like the woman, should be without ‘‘a past.” 
T. E. THORPE. 
Radiography. 
Your columns are eagerly searched every week for inform- 
ation regarding the latest developments of radiography, and for 
the best methods of working. I think it may be said that we 
are still in a state of empiricism as to the technique of the sub- 
ject. We can get fair representations of most of the bones in 
the human body, though we have much to learn even in this 
elementary detail. But the definition of the soft parts with 
sufficient accuracy for diagnostic purposes is still, so far as I am 
aware, beyond us. 
Judging, however, from occasional results, I fancy this desir- 
able point will be reached ere long ; for on examining a recent 
radiograph of a rabbit, I find the masseter muscles well defined, 
together with accurate outlines of the internal organs. In the 
case of a partridge, radiographed to discover the cause of 
“* towering,” the tendons of the thigh muscles are sharply defined, 
andina hedgehog many minute details are perfectly clear. In each 
of these I gave an exposure of seventy-five minutes, at a distance of 
14 inches with a low tension (under 3 inches). I am now using 
a Rhumkorff coil capable of giving a 10-inch spark, a Watson 
““penetrator”’ tube, and Cadett “ professional” plates. Ishould 
