330 Physiologie der Zellen, Gewebe und Organe. 



842) Hertz, A. F., and Newton, A., The normal movements of the colon in Man. 

 In: Journ. of Physiol., Bd. XLVII, S. 57, 1913. 



Under natural conditions the passage of faeces along the colon is niainly due to a 

 rapid movement along a considerable length of the bowel repeated three or four times 

 a day. The chief Stimulus for this movement is the entering of food into the empty 

 stomach. Min es. 



843) Dixou, W. E., and Halliburton, W. D., The cerebrospinal fluid. 

 L Secretion of the fluid. In: Journ. of Physiol., Bd. XLVII, S. 215, 1913. 



The secretion of cerebro-spinal fluid is markedly increased by anaesthetics 

 such as Chloroform, ether and chloral hydrate also by alcohol, choroid extract, 

 brain extract and COg. A slightly increased secretion is caused by large injec- 

 tions of water or normal saline, by Cholesterin, kephalin, atropine, Pilocarpine 

 and substances which lead to formation of methaemoglobin. No increase, or a 

 diminution was found with many tissue extracts, proteins, cerebrospinal fluid it- 

 self, lactic acid, choline, cocaine, strychnine etc. The cerebro-spinal fluid of man 

 is rieh in COg and any increase in COg or deficient Oxydation causes more cerebro- 

 spinal fluid to be turned out. It may be an important Channel of excretion 

 during nervous metabolism. Min es. 



844) ISherringtoil, C. S., Further observations on the production of 

 reflex stepping by combination of reflex excitation with reflex in- 

 hibition. In: Journ. of Physiol., Bd. XLVII, S. 196, 1913. 



Concurrent balanced faradisation of a pair of afferent nerves, one in each 

 leg of a decerebrate cat induces rhythmic stepping movements in the knee ex- 

 tensors even when the afferent nerves of these muscles have been cut. The 

 muscles sometimes "gallop" but most usually they "trot". Various explanations 

 of the nervous mechanisme of reflex stepping are reviewed. The Suggestion 

 favoured is that two reflex influences one excitatory the other inhibitory are 

 concurrently at work in closely balanced intensity; and that in the presence of 

 these the intrinsic processes of "fatigue" and of "successive induction" occurring 

 in the nerve centres produce an alternate predominance of the one and then of 

 the other of the two opposed extrinsic influences. Min es. 



845) Peters, R. A., The heat production of fatigue and its relation to 

 the production of lactic acid in amphibian muscle. In: Journ. of 

 Physiol., Bd. XLVII, S. 243, 1913. 



The heat produced during the indirect Stimulation of the leg muscles of 

 frogs in air has a maximum value of about 0.9 cal. per gram of muscle tissue. 

 About 757o is liberated in the first two minutes of tetanus. 



Chloroform rigor induced in fresh muscle liberates 1.70 cals, in fatigued 

 muscle 0.87 cals per gram. 



Since the sum of the heat produced in fatigue and that produced in the 

 fatigued muscle by the action of Chloroform is equal to the total heat production 

 in Chloroform rigor of the fresh muscle, the inference is drawn that no pro- 

 cesses of importance arise in the production of rigor other than are involved in 

 muscular contraction. Heat production and lactic acid liberation are very intima- 

 tely connected. Min es. 



846) Hill, A. V., The heat-production in prolonged contractions of 

 an isolated frog muscle. In: Journ. of Physiol. Bd. XLVII, S. 305, 1913. 



The heat production in tetanus is 20% to 40% less when the muscle is 

 allowed to shorten than when it is kept stretched. Increased frequency of exci- 



