456 Royal Society. 



184*2. This description was found by Mr. Wilson, who devoted to 

 the investigation six months of exclusive labour, to be, in many essen- 

 tial particulars, exceedingly inaccurate and erroneous. The present 

 paper contains the principal results-of the author's researches on 

 these singular animalcules, which inhabit the sebaceous follicles of 

 the human skin, and feed on the secretions that surround them. The 

 author enters into minute anatomical details of the structure of the 

 various organs, and more particularly of the apparatus by which 

 the head is retracted within the thorax, of the eyes, of the ova, and 

 the remarkable embryonic forms which are presented in the progress 

 of development of the young animal. He applies to this animalcule 

 the term entozoon, merely as signifying an inhabitant of the interior 

 of the body, and until a better and more appropriate appellation shall 

 have been assigned to it. 



A paper was also in part read, entitled, " Miscellaneous Observa- 

 tions on Animal Heat." By John Davy, M.D., F.R.S. 



December 21. — The reading of Dr. Davy's paper, entitled, " Mis- 

 cellaneous Observations on Animal Heat," was resumed and con- 

 cluded. 



The author, in the first section of this paper, after adverting to 

 the commonly received opinion that all fishes are cold-blooded, and 

 noticing an exception, as he believes, in the instance of certain fishes 

 of the genus Thynnus and of the Scomber family, describes the ob- 

 servations which he made whilst at Constantinople, on the tempe- 

 rature of the Pelamys Sarda, when, in three different examples, he 

 found its heat to exceed that of the surface-water by 7°, and of the 

 deep water probably by 12°. 



He adduces some observations and remarks on peculiarities in the 

 blood of the same fish, of the sword-fish and of the common tunny, 

 which he supposes may be connected with their temperature ; and 

 throws out the conjecture, that the constitution of their blood-globule, 

 formed of a containing and contained part, namely the globule and 

 its nucleus, may be to each other in the electrical relation of posi- 

 tive and negative, and may thereby act with greater energy in sepa- 

 rating oxygen in respiration. 



In the second section, on the temperature of man in advanced old 

 age, he relates a number of observations made for the purpose of 

 determining the actual heat of persons exceeding eighty years of age; 

 the result of which, contrary to the commonly received opinion, is, 

 that the temperature of old persons, as ascertained by a thermome- 

 ter placed under the tongue, is rather above than below that of per- 

 sons of middle age ; and this he thinks may be explained by the cir- 

 cumstance, that most of the food used by old persons is expended in 

 administering to the function of respiration. 



In the third section, on the influence of air of different tempera- 

 tures on animal heat, after alluding to what he had witnessed of the 

 rise and fall of the temperature of man on entering the tropics, and, 

 within the tropics, on descending from a cool mountainous region to 

 a low hot country, he adduces certain observations to show that in 

 this country similar changes of temperature take place in a few 



