68 PHILOSOPHICAL TRANSACTIONS. [aNNO 1736. 



Experiments on the Perforation of the Thorax, and its Effects on Respiration. 

 By IV. Houston, M. D. F. R. S.* Communicated by Philip Miller, F. R. S. 

 , An Abstract from the Latin. N" 44, p. 230. 



Tliese experiments, 6 in number, were made upon dogs and puppies. The 

 admission of the external air into the cavity of the thorax (even when both 

 sides were perforated) did not impede either the respiration or the barking of 

 the animals. When the dogs howled, the lungs protruded through the wounds 

 made in the thorax, and when the dogs ceased making a noise, the lungs 

 again went in. But what may seem paradoxical, the dilatation of the lungs, 

 in some of these experiments, was observed to be synchronous with the con- 

 traction of the thorax, and e contr^. This phenomenon the author supposes 

 to have been owing to the violent convulsive action of the abdominal muscles, 

 whereby the lower part of the lungs becoming suddenly pushed up, the air 

 would be accumulated in their upper part, which would consequently be dis- 

 tended. It is not to be supposed that this is the case in the natural, undis- 

 turbed respiratory action. From these experiments it was evident, that in the 

 natural state the lungs occupy the whole cavity of the chest, their surface being 

 in close contact with the membrane which lines the thorax. 



Observations, Astronomical, Physical, and Meteorological, for the Year 1 733, 

 made at fVittemberg. By John Fred. Weidler, Professor of Mathematics, 

 and F.R.S. N°44], p. 238. 



These meteorological and other observations, being temporary, are now 

 of no use. 



Concerning the crooked and angular Appearance of the Streaks or Darts of 

 Lightning in Thunder-Storms, By James I^ogan, Esq. N° 441, p. 240. 



Mr. Stephen Hales, in his Statical Essays, vol. ii, p. 291, mentions this 

 phenomenon of the streaks or darts of lightning in thunder-storms appearing 

 crooked and angular, as a thing not yet accounted for, and therefore he 

 guesses at a solution of it. 



The clouds are generally distinct collections of vapours, like fleeces ; and 

 therefore the rays of light through them must pass through very different den- 

 sities, and accordingly suffer very great refractions : from thence, therefore, 

 that appearance must undoubtedly arise. For it is highly absurd to imagine, 



* These experiments were made while Dr. H. was at Leyden in the years 1728 and 1729. 



