238 Proceedings of Learned Societies. 



is a vesicle inclosing a nucleus ; the second party, of which Dr. 

 Hodgkin and Mr. Lister were the chiefs, were equally certain that 

 Hewson was wrong, and that the red corpuscle has no nucleus. 

 Professor Gulliver showed, as the result of his researches from 

 1839-42, that the red corpuscle of mammalia is destitute of any 

 nucleus, while the red corpuscle of oviparous vertebrata, on the 

 other hand, always has a nucleus. Hewson having drawn his 

 description from the corpuscles of fish or fowls was quite right so 

 far ; and Hodgkin and Lister having examined only the corpuscles 

 of man were equally correct in the same restricted sense. Thus Mr. 

 Gulliver's observations not only completely cleared up the long 

 existing discrepancies between former observers, but fairly settled 

 " this vexed question of a nucleus," as it had so long been called. 



Further, he asserted that the result of his observations clearly 

 was, that the most important, because the most universal and funda- 

 mental, difference between the two great divisions of the vertebrate 

 sub-kingdom, is the presence or absence of this nucleus ; so that 

 any one possessing a good microscope could at once plainly see the 

 difference between the red corpuscles of these two divisions of ver- 

 tebrata. It was also shown that this character is perfectly good from 

 before birth, and throughout life, and in every age and sex, which 

 was more than can be said of any other single diagnostic, whatever 

 may be its importance. Hence Mr. Gulliver proposed to define the 

 two divisions as follows : — 



1. Mammalia, animals whose red corpuscles of the blood are 

 destitute of nuclei. 



2. Oviparous Vertebrata, animals whose red corpuscles of the 

 blood contain nuclei. 



He said there was no known exception to the accuracy of these 

 definitions, and that he had proved in 1889 that even the singular 

 oval corpuscles in the blood of Gamelidce were in size and structure 

 truly mammalian. 



The largest corpuscles among mammalia were shown to be those 

 of the whale, the great ant-eater, and the elephant ; and the smallest, 

 as originally described by Mr. Gulliver, those of the musk deer. 

 The largest corpuscles in the vertebrata are those of naked reptiles, 

 and the most regular or least variable those of birds. 



Thus the microscope is fairly enlisted into the service of sys- 

 tematic zoology. The subject was followed out in detail throughout 

 the different classes and orders ; and so plainly, that an observer 

 might, by remarking the structure of the blood corpuscle, arrive im- 

 mediately at results which, without the aid of the microscope would 

 have formerly puzzled the most eminent comparative anatomists. 

 One minutest drop of the blood, for example, of the duck-billed civa- 

 ture, Ornitlwrynchus paradoxus, would have shown it to belong to 

 the mammalia, and this even in the most immature specimen ! 



The following suggestions have been made by Professor Gulliver. 

 Reverting to his discovery of the microscopic structure of the red 

 corpuscles of ihe blood being a better diagnostic than any hitherto 

 offe red between the two great subdivisions of the vertebrata, he now 

 suggests that the intimate structure of the latex may afford good bota- 



