respiratory quotient following the intake of oxygen after asphyxiation should be smaller than when the animal is in air. He found, however, that the respiratory quotient does not essentially change and concluded from this that storage of oxygen does not take place. In these experiments, however, there exists no certain indicator as to the state of the spinal cord during asphyxiation and recovery in the given case. The spinal cord may be severely injured and even undergo degeneration during asphyxiation, and the recovery following the reintroduction of oxygen may be either incomplete or nil, without there being a method for its determination. Apart from this, _Lesser_[73] has already emphasized, in opposition to these experiments, that the respiratory quotient in recovery is no criterion to guide us. It is immaterial whether during asphyxiation oxygen respiration occurs following a reserve supply, or that an anoxydative formation of carbon dioxide has taken place, for in both instances the respiratory quotient would be less _after_ asphyxiation when there is again an oxygen supply. It is, therefore, quite impossible to decide the question by the employment of this method. For this reason _Lesser_ has attempted to solve the problem by means of quite another method, and was convinced that he had refuted finally the belief in the existence of reserve oxygen. His method consists in the employment of the _Bunsen_ ice calorimeter, by which he determines the heat production of frogs, kept first in air, then in nitrogen, and at the end of each experiment ascertaining the amount of output of carbon dioxide, respectively in air and nitrogen. He found that the quantity of heat, calculated in terms of 100 grms. body weight per hour, produced in nitrogen was considerably less than that under corresponding conditions in air, but that the production of carbon dioxide, on the other hand, during the first hours in nitrogen was doubled in amount, as compared to that in air. From this he concludes that the carbon dioxide formation in nitrogen must be different from that in air, as it is associated with a reduced heat production. In other words, carbon dioxide formation, while the animal is in a nitrogen atmosphere, does not have its origin in oxydative processes at the cost of stored up oxygen. I regret that I am unable to accept these arguments as conclusive evidence against the assumption of an oxygen reserve, as this question cannot be decided by the use of such methods. _Lesser_ does not measure the amount of carbon dioxide until the end of his experiments, that is, he learns merely the entire carbon dioxide production during a period of many hours. No conclusions can be drawn from this as to the conditions existing in the first period of time, directly after the animals have been subjected to an atmosphere of nitrogen. It is quite possible that subsequent to the change to nitrogen an oxydative carbon dioxide formation may have