408 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS THE LECTURER: Further investigations showed no sign whatsoever of •changes caused by the intake of basic particles. DR. L. GOLBERG: What about sensitization ? THE LECTURER: Our tests lasted 140 days and we used quantities far in .excess of what one would expect to meet in practice. We did not observe any hints of sensitization on hamsters, rabbits or monkeys. DR. L. GOLBERG: The reason why I harp on sensitization is not only this particular case to which I referred but when one reads the original papers of Bergmann et al (9,10)--assuming that there was a connection between the cases he described and the inhalation of hair spray--all these changes in the lung, the interstitial fibrosis and other histopathological changes, ! think, point not merely to storage. The whole question has been bedevilled by the use of this word "thesaurosis" which I think was a misnomer in the first place. It is not really storage that is important, it is the reaction, and this may be considered in some respects as a hypersensitivity response. That is why this avenue of approach is still of importance but, of course, how one can elucidate the problem on an animal basis is a very difficult question. THE LECTURER: I agree that the problem of sensitization is one of the most difficult. •IR. T. HARRIS: How do you know that the fluorescent areas seen under the fluorescence microscope are due to the presence of polyvinylpyrrolidone and not to the fluorescor itself ? If, on the other hand, the fluorescence is given by a PVP/fluorescor .complex, then the rate of disappearance of the fluorescent particles will not, strictly speaking, be properly related to the PVP, as the physical properties of the latter will have been appreciably changed. THE LECTURER: We have carried out basic experiments which convinced us that these are in fact PVP particles. Unfortunately I am not permitted to go into details. MR. A. W. POND: You said that the hair spray particles had disappeared .after 3-5 days. Had they disappeared just from the lungs or from the whole organism, i.e. had they been transferred to other organs such as the liver or spleen ? Inhalation studies and histopathological studies have been carried out in the U.S.A. on hair sprays most of which have contained water-soluble of water-dispersible film formers. On the other hand, the M.R.C. mass radiography checks have been done on hairdressers most of whom will be using shellac-based sprays.

INHALATION AND TOXICITY STUDIES 409 It would appear probable that the reaction to water-soluble and water- insoluble particles in the body might well differ. Would it not be advisable to carry out more histopathological studies on shellac inhalation ? THE LECTURER: I can say that five days after the last application no traces of hair spray particles could be found in any organ. DR. P. H. WITJENS: Do you have any figures on the particle sizes of the aerosol inhaled, or of the distribution of sizes ? THE LECTURER: We did not measure any particle sizes. DR. P. H. WITJENS: Did you use standard aerosol packs, or were they specially prepared ? THE LECTURER: We used a commercial product in order to obtain realis- tic conditions.