respiration cycle for example only during inhalation in this manner a simple on off switching operation can be realised according to the invention i e nebulisation starts when inhalation begins and ends once inhalation is complete however it was established during the tests based on the invention that the respiration signal of the oscillatable structure 1 6 7 which is usable according to the invention allows for considerably more accurate information regarding the respiratory cycle of the patient namely even if the activation signal is also supplied to the oscillatable structure 1 6 7 via the connecting lines 8 and 9 in other words the two signals namely the activation signal of the control means 10 by means of which the oscillatable structure 1 6 7 is caused to oscillate and the output signal of the oscillatable structure 1 6 7 caused by the respiration of the patient superpose one another in an almost distortion free manner this is quite surprising since the output signal at the connecting means 8 9 of the oscillatable structure 1 6 7 which is caused by pressure fluctuations is much smaller than the activation signal which is fed from the control means 10 to the oscillatable structure 1 6 7 via the connecting lines 8 and 9 therefore when using the invention optical or acoustical indications can be given to the patient to optimise respiratory flow or aerosol generation can be automatically shut off if too high respiratory flows are detected which are unfavourable for a safe intrapulmonary aerosol deposition in order to ensure a reliable separation.