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The determination of carbon dioxide in carbonato-apatites is carried out a new gasometric method. Its application, in this paper, concerns the bones of skull and mandibles of Cory's shearwater (Calonectris diomedea borealis) and Mallard (Anas platyrhynchos). The results lead to appreciable differences between some organs of this two species.

The chicken digestive tract is mainly colonized by bacteria belonging to the Lactobacillus genus. One of these strains (LEM-207) isolated from the crop of a cock and closely resembling L. acidophilus, was able to develop on a carbohydrate-free medium. Production of carbon dioxide and synthesis of tyramine, putrescine and cadaverine were observed in the cultures. Once implanted in the crops of germ-free chickens, strain LEM-207 led to the formation of amines. In germ-free (axenic) animals, only endogenous tyramine was detected, whereas in monoassociated chickens, we found a production of tyramine, cadaverine and putrescine. The concentrations of cadaverine and putrescine decreased with increasing acidification of the contents, whereas the level of tyramine increased (7-fold higher level than in germ-free chicken). Amine production was not detected in the caeca. The toxicological aspects of tyramine production in terms of the animal are discussed.

The classification of harmful gases may be envisaged in various ways according to the criteria considered. The two aspects adopted here concern chemical and toxicological classifications. Chemical classification is in general based upon the nature of the elements constituting the gases, e.g. carbon, nitrogen, sulphur, phosphorus, halogen compounds and halogenated compounds, etc. Toxicological classification is envisaged on the basis of the concepts of toxicity itself. It may then be used to establish the scale of its degree based upon two principal factors: concentration and duration of exposure. However, certain observations suggest complex intoxication phenomena related to an overall number of factors which are generally considered in isolation.

The cool flame combustion of polypropylene at 350 degrees C leads to the formation of toxic compounds which can cause death in mice. Under the conditions described, the LD50 is close to 0.95 g. However the survival times with 0.50 g samples are longer than those obtained by operating in an ambient atmosphere at 500 degrees and 800 degrees C after a slow introduction of the material into the oven.