The study of gastric and intestinal motility in man and animals by balloonkymography has a long and fruitful history (Alvarez, 1948). By this means valuable information has been obtained of normal motility and its behaviour in diseasfi and under the influence of drugs, food and emotion. This method of investigation is, however, open to many criticisms. It is uncomfortable and tedious, affecting intestinal behaviour in a number of possible ways by (i) affecting the higher centres; (ii) distension of the gut by the balloons, stimulating stretch rece])tors; (iii) interference with venous return; (iv) acting as foreign bodies.Some of these objections apply to any method which has been used, although tliat of Quigley and Brody (1952) is probably the least objectionable. They have stated that the conventional water manometer has a natural frequency of less than 1 cycle/second and therefore is incapable of measuring rapid changes in pressure. They have claimed that, by using open-end tubes coupled to an optical manometer, frequencies of 25 cycles/second can be recorded, and that, as quite large prps.sure changes of one second duration can occur, tliese would escape recognition when conventional apparatus with closed ends is used.It is impressive that the results observed by many investigators using different methods have been similar. Whatever the effects may be of the artificial stimuli from the use of balloons, results which have been obtained in this study show that it is unlikely that they seriously upset the validity of the experiments. One would expect effects due to the method used, and operating throughout a given experiment, to influence the result in a regular way and to show up, by inhibition or increasing augmentation, as the record proceeds. But it has been repeatedly observed that periods of quiescence and activity occur at any time in the record, some showing marked activity at the beginning, others only towards the end. The variety of patterns recorded, and their great complexity, are in themselves indications that tlie gut is behaving, to some extent anyhow, untrammelled by the harness applied.of this work was parried out during the tenure of the "Sol Green Research Scholarship," Alfred Hospital, Melbourne.
