Now, Strangeways has shown that it is impossible by radiography to detect _tophi in bones_. Accordingly we have at present no means of deciding in any given case whether the localised _transparent areas_ in the bones are due to _tophi_ or to _focal absorption_ of lime salts. If we are to cling to the conception that they are due to _tophi_, then it is clear that _tophi in the bones_ are more common than is currently suspected, and that, _ergo_, the frequency of gouty arthritis is underestimated. For these transparent foci in bones, according to McClure and McCarty, occur in from 10 to 12 per cent. of cases of chronic arthritis “which clinically are not gout.” Yet these authorities hold that, despite the fact that they occur in cases of _non-gouty_ arthritides, they have some diagnostic significance. For, taking the work of other observers in conjunction with their own observations, they come to the following conclusions:— (1) The focal areas of decreased density, heretofore considered as peculiar to gout, are rarely absent in that disease. (2) Their absence would be some evidence against the existence of gout in a given case. (3) On the other hand, their presence is no more than suggestive of gout, since they are found in from 10 to 12 per cent. of cases which clinically are not gout. (4) The focal areas of decreased density, usually held due to tophi, are probably very often merely focal areas of absorption of lime salts. In continuation these authorities have endeavoured to identify the nature of the _arthritis_ that occurs in _gout_. Like other workers in this sphere, the study of the radiographs obtained of gouty joints reveals that a variety of changes occur in the bones and joints of the hands and feet in gouty subjects. These, they consider, may be classified conveniently as follows:— (1) Cases marked by _focal areas of rarefaction_, without any other perceptible change; (2) Cases presenting, in addition to these translucent areas, minor degrees of lipping at the articular margins; (3) Cases in which the changes in (1) and (2) are conjoined with either localised atrophy of the bones entering into an affected joint, or with generalised atrophy of all the bones in the affected limb; (4) In addition to all the above changes, narrowing of certain joint spaces with marked proliferative and atrophic changes occurs.