CHAPTER V 



TRACE ELEMENTS IN ANIMALS 



The study of trace elements in animals has not proceeded so 

 far as with plants, but analysis has shown that animals, no less 

 than plants, may contain small amounts of many elements not 

 generally regarded as essential. The well-established indispen- 

 sable elements are carbon, hydrogen, oxygen, nitrogen, sulphur, 

 phosphorus, sodium, potassium, magnesium, calcium, iron and 

 chlorine. Fox and Ramage (193 1), 1 by spectrographic examina- 

 tion of forty -three whole animals, separated tissues of eighteen 

 others and blood of three more, found that in addition to the 

 above-named essential elements copper was universally present. 

 Manganese was also found to be widely distributed. Cobalt and 

 nickel were also found to be present in a number of species, 

 nickel being met with more frequently than cobalt, but the 

 incidence of both appeared to be irregular. Lithium and stron- 

 tium were also found in many of the species examined, while 

 lead, silver, and rubidium were found in several. Cadmium and 

 calcium fluoride were each found in one instance only. 



The flame method of spectrographic analysis used by Fox and 

 Ramage (cf. p. 28) is not applicable for the detection, and still 

 less for the estimation, of a number of elements, including 

 aluminium, arsenic, boron, antimony, bismuth, gold, molyb- 

 denum, tin, titanium, uranium, vanadium and zinc, all of which 

 had earlier been recorded as occurring in at least one animal. 

 In a later spectrographic examination of marine invertebrates 

 made by Webb (1937) the silver and carbon arcs were used, by 

 means of which these elements are detectable in small amounts. 

 Twenty-one marine animals, as well as three algae, were ex- 

 amined ; the animals included representatives of Gastropoda, 

 Lamellibranchiata, Echinodermata, Pisces, Urochordata, Crus- 

 tacea, Nemertea and Polychaeta. 



As far as those elements which are also detectable by the flame 



1 References to earlier literature on trace elements in animals are to 

 be found in this paper, and in that by Webb referred to below. 



