. Microbes & toxins. Bacteriology; Toxins; Antitoxins. PHYSIOLOGY OF THE MICROBES 101. Fig. food: â An amoeba expelling the residue of its various stages. (After Verworn.) acid, then alkaline, just as in the stomach and small intestine of mammals. The solid refuse of digestion is evacuated by an anus and the liquid residue collects inside protoplasm in a little spherical sac which from time to time ex- pels its contents externally: this latter is the con- tractile vesicle which Ehrenberg took for the pul- sating heart. Oxygen is a primary necessity to protozoa as to bacteria: the dige
. Microbes & toxins. Bacteriology; Toxins; Antitoxins. PHYSIOLOGY OF THE MICROBES 101. Fig. food: â An amoeba expelling the residue of its various stages. (After Verworn.) acid, then alkaline, just as in the stomach and small intestine of mammals. The solid refuse of digestion is evacuated by an anus and the liquid residue collects inside protoplasm in a little spherical sac which from time to time ex- pels its contents externally: this latter is the con- tractile vesicle which Ehrenberg took for the pul- sating heart. Oxygen is a primary necessity to protozoa as to bacteria: the digestive vacuoles contain oxygen, the contractile vesicles discharge carbonic acid, , aerobic respiration. The protozoa which live in surroundings deprived of free oxygen have, it is certain, a method of respiration analogous to that of anaerobic bacteria; they draw their oxygen from reserve materials which they have stored within themselves, , glycogen. It is believed, without being absolutely certain, that certain infusoria can, like the intestinal worms (ascarides), break up glycogen with the formation of valerianic and carbonic acids. Among the products of excretion have been found uric acid and phosphate of lime (Schewiakoff). Excretion is a fairly active process since the vacuole contracts often (every four to eighteen seconds according to temperature in Stylonychia pustulata). According to Maupas the infusoria discharge during a space of time which varies from two to forty-six minutes a volume of liquid equivalent to the whole voluthe of the animal. Stimulation from the exterior is always accompanied in the protozoa by a manifestation of energy : they possess irritability. The excitant may be a touch, a ray of light, heat, electricity or a chemical substance, and the protozoon in its reactions to the stimulus acquires habits such that its physiology is full of as many problems as that of the higher animals, not excepting problems in psychology. Although possessing
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectantitox, bookyear1912
