93 



that ic is not milk. M. Durnas has obtained this result still more 

 positively by microscopic observations, Each of these products 

 is invariable in its form : milk has the appearance of perfectly sphe- 

 rical globules ; while the matter from the gland of the Water-Rat 

 exists under the form of thin flakes strongly angular at the edges. 

 The mucus of the saliva presents the šame aspect, except that the 

 edges of the flakes are not so deeply indented. The result is, that 

 the glandular secretion furnished by the IFater-Bat appeared to us 

 to be mucus mixed with a small proportion of fatty odorous matter; 

 and there can be no doubt that the šame is the case with the secre- 

 tions of the glands of the Shrews. 



" Now there remains an experiment to be made by the Zoological 

 Society, but principally b}' Mr. Owen, animated likę myi-elfvvith 

 zeal for scientific truth ; and which I invite my colleagues to make. 

 Alcohol does not alter the form of the elementary molecules, either 

 of milk or oP mucus. Mr. Ovven has deposited in the Museum of 

 the College of Surgeons his anatomical preparations ; it is easy, 

 without damaging the preparations, to take from the monotrematic 

 apparatus a small quantity of its secretion, and to place ii iu the 

 field of% microscope. An ansvver will thus be obtained, of vvhich I 

 admit beforehand all the consequences. 



" The negative characters indicated above, (no conglobate tissue, 

 no erectile tissue, no nipples,) are remarkable concessions on the part 

 of Mr. Ovven. He might have advanced still further in the šame 

 direction, and not have accepted, for example, from Lieut. Maule 

 his milky fluid only, reserving himself to combat aftervvards vvhat 

 that observer says de visu of the shellsin the nešt, and rejecting also 

 the ojiinion of the country in favour of the oviparous character of 

 the Monotremuta. 



" But I vvill not return here to all the accessory points of the con- 

 troversy : I pass to Mr. Ovven's observations in reply. 



" Firstly, To destroy the effect of the analogy of the glands of 

 the Shretvs, to vvhich I had referred the glands of the Monotremata , 

 Mr. Ovven cites the authority of Von Baer, who in the Archives of 

 Anatomy and Physiology, published at Leipzig in 1827, p. 168, had 

 combatted my vievvs, in order to support the opinions of his friend 

 and fellovv-countryman Meckel, remarking that, proceeding from 

 analogy to analogy, that of the Cetacea mušt also be taken into con- 

 sideration. Von Baer says that the structure of the glands of the 

 Ornithorhynchus, as described and figured by Meckel, reminded 

 him in all particulars of the mammary glands of the Cetacea ; and 

 actually refers to a similar arrangement in the Porpoise. Now, adds 

 this learned anatomist, ' it has never entered into the mind of any 

 man to deny the Porpoise to be a lactiferous animal.' It is true 

 that nobody has hitherto raised a doubt on this point ; but it woul3 

 not be by any means extraordinary if we vvere obliged to do so now, 

 ifit were certain, as I believe, that the monotrematic glands of the 

 Ornithorhynchus give rise to a nevv mode of nutrition as regards the 

 young. For if this were the fact, the Cetacea vvould participate in 

 this nevv mode, in these nevv functions^ which it vvUl become uite- 



