96 PROCEEDINGS OF THE ACADEMY OE 



April 3d. 



Vice President Bridges in the Chair. 



Fifty members present. 



A paper was presented for publication, entitled, " Conspectus Piscium 

 in expeditione ad Oceanum Pacificura Septentrionalern, C. Ringgold et 

 J. Rodgers ducibus, a Guilelmo Stirnpson, M. D., collectore ; Sicydianae: 

 auctore Theo. Grill." 



Mr. Lesley read the following extract from a letter received from 

 Mr. T. S. Hunt, Chemist of the Canada Geological Survey, dated 

 Montreal, March 25th, 1860 : 



"If we mingle in equivalent proportions the chlorides of calcium and 

 magnesium in concentrated solution, and then having precipitated the bases 

 by a slight excess of carbonate of soda in the cold, and expose the mixture for a 

 few hours in a closed flask to a temperature of 200 212 F., the pasty mass 

 is entirely transformed into a beautiful granular powder, made up of spherical, 

 translucent, crystalline grains, which are sparingly soluble in cold, dilute, acetic 

 acid and are a double carbonate of lime and magnesia. In my previous and 

 published trials, at temperatures of 300 400 c F., the product was much less 

 beautiful, and was mingled with carbonate of magnesia. It now remains to 

 be seen whether the combination may not be slowly effected at a temperature 

 much below 200 F., and experiments upon this point are in progress." 



Mr. Lesley drew the attention of the Academy to the significant direction 

 in which these and similar experiments are carrying the chemical geology of 

 the day. If they result in nothing more than the destruction of those igneous 

 prejudices which still shackle observers, especially in metamorphic mineral re- 

 gions, and set us free to study ab initio the phenomena of magnetic iron veins, 

 copper lodes and gold quartz, primary limestones, serp^ptmes and dolomites, 

 the consequences must be practically important. 



Mr. Foulke remarked the equally important bearing the low temperature 

 of these experiments must be seen to have, on the theory of non-fossiliferous, 

 primary rocks. If metamorphism has been possible at such low temperatures, 

 the argument in favor of the destruction of organic remains from metamorphic 

 strata by fiery agencies is of force no longer, and we must conclude that these 

 early and apparently non-fossiliferous rocks were really destitute of life. 



Dr. Leidy stated that he had just received a short notice from Prof. 

 Leuckart, of Giessen, in which he mentions the results of some experiments 

 with Trichina spiralis. Having fed dogs with human flesh containing 

 Trichinae, he found that in a week or less, the worms completed their devel- 

 opment, but without assuming the form of a Tricocephalus or Strongylus. 

 Within the intestine of the dog, the generative apparatus, together with the 

 eggs and embryos, were fully developed in the Trichina?. The embryos 

 rapidly pass away with the excrement of the dog. A pig having been fed with 

 a dog's intestine containing fully developed Trichinae, was killed and dissected 

 on the 3d of March, and exhibited in the muscles millions of Trichinae. From 

 these facts it is rendered probable that embryos of Trichina voided by dogs 

 find their way into the human stomach through the food or drink, and sub- 

 sequently burrow into the tissues of the body. 



Nott. The date of tho meeting of the Academy on page 51, should be Feb. 14th, instead of 

 Feb. 11th. 



[March, 



