Topinard (1872:211) subsequently turned his attention to these mainland Australians when Eugène Simon, the French consul in Sydney, and a Dr Jules Goyard requested instructions regarding the anthropological observations of Australian Aborigines that travellers might make where the opportunity arose. These 'instructions' were published in the Bulletins (Topinard 1872). They show that when Topinard applied himself to a detailed study of the available literature, the racial judgments he had earlier made of the mainland groups were tempered by reflection on the information before him. He formed the view that the Aboriginal population of mainland Australia comprised 'three orders of tribes': inferior and superior, with an intermediate type that showed a blend of features arising from their intermixing. Topinard had taken up the first-hand observations of a number of explorers, officials, and missionaries,^[21] combined these with his own studies of the Australian skulls in Paris, and reworked this material to propose a theory of an inferior negroid type occupying mainly the coastal regions and a superior type, the 'bush Australian', inhabiting the remoter parts of the continent. He described the superior type as handsome, tall, and well proportioned, stately in bearing, proud, brave, intelligent, and with long, wavy hair; the inferior type he portrayed as ugly, small, and stupid with frizzy hair, using such demeaning terms as 'ill-favoured' (disgracié), 'repulsive' (hideux), 'wretched' (misérable), and 'puny' (chétif). According to Topinard, his two types were the descendants, no longer existing in their pure form, of two original 'races', the superior 'Dravidian' race having displaced the 'negroid' type.^[22] He maintained that the favoured race took over the best land leaving the less fertile littoral regions to the 'pariah race'. The pariahs, he supposed, were autochthonous and belonged to the 'true Melanesian race'. They were identical to the 'black New Caledonians' who represented his pure Melanesian type.^[23]

When Topinard met Billy, Jenny, and little Toby, he saw physical confirmation of his two races theory, immediately assigning them to his second category. His difficulty in seeing beyond physical appearance is evident here and contrasts with Virchow's report on Cunningham's troupe who had spent several weeks performing in Berlin in 1884. Virchow (1884:414‑16), like Topinard, had been most concerned to conduct an anthropometrical appraisal of the Queenslanders. But, unlike Topinard, he had no difficulty in making a distinction between inner states and capacities and outer appearance. He found the Queenslanders physically unattractive but, as if addressing a racially hostile interlocutor, he took pains to make a number of relatively positive observations about the mental and psychological qualities of different members and of the group as a whole when compared to Europeans. He responded to each of the Aborigines as separate individuals with distinct personalities. He praised the grace, composure, and prowess of their physical performances. And, as a committed monogenist, he had no hesitation in seeing them as 'true men' in every respect.

Much of Topinard's 1872 paper 'Sur les races indigènes de l'Australie' rehearses descriptions of the way Aboriginal men and women looked to the voyagers and explorers who wrote about them. When it came to aesthetic evaluations of different ethnic or indigenous groups, most commentators unquestioningly applied European standards of beauty. The narratives and scientific treatises issuing from voyages of exploration were especially detrimental to Aboriginal Australians in their physical descriptions, as Topinard (1872:229, 231) acknowledged in relation to the writings of Dumont d'Urville. Topinard explained the reported differences in Aboriginal appearance in terms of his theory of two distinct racial types and an intermediate form:

In particular, Topinard's review of reports about the appearance of Aboriginal women shows how easily the science of race could descend into fantasizing and voyeuristic attraction or repulsion. In keeping with his two types thesis, he found two extreme versions of Aboriginal womanliness (1872:261): 'one of them, everything that is most hideous, bestial and repulsive in the world; the other composed of women who are well formed, with broad backs, slim waists, ample and well developed busts, and with very pleasant features and overall appearance'. In such an intellectual climate, gender and race stereotyping easily became conflated and intensified. Topinard (1872:252) imagined continual 'crossings' between the two main racial types over the centuries and maintained that 'It is the female sex which preserves the most pronounced characteristics of the most primitive type for the longest time and it is there that we will find its purest traces'. His unease about Jenny and the harshness of his descriptions of her suggest this kind of conflation and intensification of stereotyping in relation to an anthropological subject who is disturbingly and doubly different.^[24] Yet, this is easy to say and to condemn, as if sexual, gender, and identity anxieties were purely nineteenth-century phenomena, ignoring our own era's investment in such critiques.^[25]

Topinard was always primarily concerned with anatomical and morphological data as shown in his presentation of the members of Cunningham's troupe. This blinkered perspective limited his capacity to comprehend human differences. The ethnographic information paraphrased in his 1872 study (1872:278, 285) gave him no insights into Aboriginal social and cultural life. With respect to religious sentiment, for example, he pronounced negatively: 'They have neither cult, nor ceremony, nor idol, nor any object of worship that might take their place'. The chastity of Aboriginal women was a 'thing unknown'. But writing several years later in another register, Topinard was much more alert to positive aspects of Aboriginal adaptation to the Australian environment and reproved the British colonizers:

In fact, Topinard's two races theory of Aboriginal origins can be read as an expression of his ambivalence about the contemporary anthropological zeal for ranking human groups on a scale from higher to lower, superior to inferior, forms of humanity. He had reviewed a large volume of literature about Aboriginal Australians and found the evidence contradictory. But his binary theory enabled him both to praise and condemn Aborigines. The human ladder was a major blindspot of raciology which scarcely questioned the scientific, let alone the humanitarian validity of ranking. Once the human 'varieties' of the eighteenth century became reified as 'races',^[26] measurable and observable features such as skin colour, head shape, hair type, nasal index, prognathism, ratio of upper leg to lower leg — features overwhelmingly associated with stereotyped sub-Saharan Africans — were assigned values indicating higher or lower. With the accumulation of comparative data, unexpected mixtures of putatively inferior and superior features in the one race, such as the dark skin of Indigenous Australians combined with non-'negroid' hair, led either to confusion or to implausible qualifications by scientists who had to explain the presence of superior features in what was held to be an inferior race, or vice versa.^[27]

In a detailed and historically useful discussion of the notion of race, Topinard (1879:660) referred only once to the concept of a racial hierarchy when he concluded his paper with Broca's definition of the term 'ethnology' as the description and determination of human races, including 'their respective position in the human series'. This is an anodine formulation for ranking by race which ultimately Topinard accepted as a basic tenet of anthropology.^[28] He did not, however, follow Broca's pronouncements about unproductive unions between Europeans and Aborigines. Indeed, he cited the historian James Bonwick (1817-1906) to the effect that the children of Tasmanian Aborigines and English 'are as fertile as the Europeans and are prospering' and he anticipated a future racial melting pot, where in effect the multiplicity of human origins had given way to increasing human uniformity — but the 'inferior' races had died out.^[29]

Topinard was wholly committed to the natural science approach to the study of human difference in which humans beings had to be subject to the same objective methods applied to animals. In his famous manual L'Anthropologie he proclaimed: