The present paper is primarily concerned with the real significance of Ayala's rachidian quotient (RQ). Having in sight the considerable disagrea-ment found in the literature on the matter, the author has studied the RQ in order to determine normal parameters of RQ for every taken volume of CSF between 2 and 15 ml, since, from the development of Ayala's formula, RQ resulted a proportional variable in relation to volume taken. Results obtained may be seen in table 2. It was devised a method to calculate RQ for a standard volume if one has determined RQ for any volume taken, allowing, in this way, correct interpretation of results. Development of formulas may be seen in the text.