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WHERE DOES THE HUMAN REMAIN IN ANATOMY?

SIR,-On Aug 11-16 the XIIth International Anatomical

Congress was held in London. More than a thousand scientists camefrom all over the world, and in symposia, lectures, and postersessions a huge number of studies on the morphology and functionof cells and tissues were presented. I was surprised at the poorrepresentation of human investigations. Of the 810 abstracts in thecongress proceedings 534 (66%) were mainly about experiments onnon-human animals, including fish and birds besides rodents.Studies on human cells and tissues were reported in only 196 (24%)papers. The remaining 80 related to the teaching of anatomy or weredrawing attention to reviews. In a few abstracts the origin ofspecimens was not mentioned.This disadvantageous ratio between non-human and human

studies in anatomy may result in uncritical data transfer from one

species to the other-eg, results obtained by careful examination ofmicrovascular blood supply of the spleen from dogs, cats, androdents cannot be transferred to man since the morphology andfunction of the spleen differ greatly between the species. Resultsobtained in other animals have to be carefully revised for man. Thispresupposes close cooperation between clinicians and purescientists. Since the vast majority of those attending anatomicalcongresses also teach anatomy to medical students, bettercollaboration between anatomists and clinicians may be beneficial.

Division of Cell Biology,Department of Anatomy,University of Zürich,CH-8052 Zürich, Switzerland P. GROSCURTH

SORGHUM IN OESOPHAGEAL CANCER

SIR,-Dr Oterdoom (Aug 10, p 330) asserts that "in 1970 the realcause of this nasty cancer was revealed", referring to the hypothesisthat sorghum is the cause of oesophageal cancer. He writes that "inKenya, through Zambia and the Transkei, people use a lot of brownsorghum". Quite so; the trouble is that there are areas in Africawhere carcinoma of the oesophagus is endemic yet there is no

sorghum about (Muranga, Moshi, Chipata), and others, wherethere is plenty of sorghum, yet cancer of the oesophagus isuncommon (Gulu, Kapenguria).Smoked fish (Kisumu), oil drums for distilling (Transkei), home-

brewed beer (Chipata) have all been implicated as "the cause" ofthis carcinoma. So were smoking, alcohol, hot food, spices, lack ofmolybdenum, and the lack of zinc in the soil. Since this canceroccurs in clusters elsewhere-in Brittany (France), in several partsof China, and on the shores of the Caspian Sea-it is perhapsinadvisable to speak about a "real cause".

Nairobi Hospital,PO Box 47964,Nairobi, Kenya IMRE J. P. LOEFLER

ASTHMA OUTBREAK DURING A THUNDERSTORM

SIR,-May we add yet another piece of information to the study byDr Packe and Dr Ayres (July 27, p 199) by reporting a hithertounknown type of air pollution which could also have contributed tothe asthma outbreak and to acid rain. 1The Morrow Brown spore trap2 sucks 10 litres of air/min through

a slit 0 - 5 mm wide instead of the usual 2 - 0 mm. This modification

improves trapping efficiency for small spores and increases impactvelocity to the extent that, while investigating alternative adhesivesto ’Vaseline’ in 1982, we found that spores will stick to a slide withoutadhesive, so that they can be examined without mounting, whilepollen grains bounce off. During the asthma outbreak in 1983 bothvaseline coated and plain slides were being exposed, and on the plainslides enormous numbers of spores were seen to be accompanied bymany crystals of all shapes and sizes (see figure).The crystals have since been observed at a rural as well as an urban

site, and appear in showers at certain times of day or night only. Theoptimum weather conditions are, as yet, unclear. The crystals

dissolve in or are rendered invisible by the polyvinyl lactophenolslide-mounting medium, which explains why they have not beenobserved previously.

Appearance of calcium sulphate crystals found on plain slides inspore trap during 1983 asthma outbreak in Derby.

Upper: SEM, illustrating crystal pleomorphism (x4400).Lower: light microscopy, with feathery crystal and spores (x 800).

M. F. Page and. Bates, ofthe department of material technology,Loughborough University, carried out scanning microscopy (SEM)for us and analysed the crystals by energy dispersive X-raymicroanalysis and X-ray diffraction. All crystals examined wereidentified as the anhydrous form of calcium sulphate, which is verypleomorphic. The most likely source may be the many coal-firedpower stations within 25 km of Derby, which lies in the largest areaof sulphur emissions in England.3Perhaps these crystals of calcium sulphate could trigger spasm in

hyperreactive bronchi, thus contributing to asthma epidemics.Production of an aerosol for provocation tests has been unsuccessfulso far.

Midlands Asthma and AllergyResearch Association,

12 Vernon Street,Derby DE1 1FT

H. MORROW-BROWNF. A. JACKSON

1. Editorial. Acid rain toxic metals. Lancet 1984; i: 659-60.2. Brown HM, Jackson FA Aerobiological studies based in Derby I: a simplified

automatic volumetric spore trap. Chn Allergy 1978; 8: 589-973. Martin A, Barber FR Some observations of acidity and sulphur in rainwater from rural

sites in central England and Wales Atmosph Envir 1978; 12: 1481-87.