604 PHILOSOPHICAL TRANSACTIONS. [anNO 1775. 



resolved still to send you the above account, that you might judge for yourself. 

 I observe, that his account or description and mine differ in several things ; and 

 among others, where he says, that those fish were usually about 3 feet in 

 length ; but the one, of which I have sent a slight description, was 3 feet 

 8 inches. He was told, that some of these fish have been seen in Surinam 

 river, upwards of 20 feet long, whose stroke or shock proved instant death to 

 any person that unluckily received it. 



XII. Experiments and Observations in a Heated Room. By Charles Blagden, 



M. D., F.R.S. p. 1 11 . 



About the middle of January, several gentlemen, with Dr. B., received an invi- 

 tation from Dr. George Fordyce, to observe the effects of air heated to a much 

 higher degree than it was formerly thought any living creature could bear. They 

 all rejoiced at the opportunity of being convinced, by their own experience, of the 

 wonderful power with which the animal body is endued, of resisting a heat vastly 

 greater than its own temperature ; and their curiosity was not a little excited to 

 observe the circumstances attending this remarkable power. They knew indeed, 

 that of late several convincing arguments had been adduced, and observations 

 made, to show the error of the common opinions on this subject ; and that Dr. 

 Fordyce had himself proved the mistake of Dr. Boerhaave* and most other au- 

 thors, by supporting many times very high degrees of heat, in the course of a 

 long train of important experiments ; with which he hoped Dr. F. himself 

 would favour the public. In the mean time. Dr. B. was happy in an opportunity 

 of laying before the r. s. the following short account of some of these experi- 

 ments, and of the views with which they were undertaken ; for the particulars 

 of which he was obliged to Dr. Fordyce himself. 



Dr. Cullen long ago suggested many arguments to show, that life itself had a 

 power of generating heat, independent of any common chemical or mechanical 

 means ; for, before his time, the received opinions were, that the heat of ani- 

 mals arose either from friction or fermentation. -|- Governor Ellis, in the year 

 1758, observed,:): that a man can live in air of a greater heat than that of his 



* Elem. Chemiae, torn. I, p. 277, 278. — Orig. 



f To do further justice to the philosophy of this most ingenious and respectable professor. Dr. B. 

 declares^ that during his stay in Edinburgh, from the year 1765 to 1769, the idea of a power in ani- 

 mals of generating cold (that was the expression) when the heat of the atmosphere exceeded the 

 proper temperature of their bodies, was pretty generally received among the students of physic, from 

 Dr. Cullen's arguments ; in consequence of which he appUed a thermometer, in a hot summer day, 

 to the belly of a frog, and found the quicksilver sink several degrees : a rude experiment indeed, but 

 serving to confirm the general fact, that the living body possesses a power of resisting the communi- 

 cation of heat. — Orig. 



X Phil. Trans., vol p. 755.— Orig. 



