(Kmoch, et ai, 1975; Reznik, et ai, 1975b; Kmoch, et ai, 1976). Its size also 
means that biochemical studies to establish metabolites of carcinogens in the 
larynx, trachea and lungs are likely to be more successful than similar studies in 
th'e Syrian golden hamster, since the experimenter has significantly more tissue 
at his disposal. 
As is well known, C. cncetus is a hibernator (Fig. 0-2) (Kayser, 1961; 
Precht, et ai, 1973) and, according to the reports of zoologists, should live up to 8 
years of age (Gaffrey, 1961; Zimmermann, 1965). Accordingly, we attempted to 
establish a breeding colony under laboratory conditions (Mohr, et ai, 1973; 
Reznik-Schiiller, et ai, 1974a). The problem of breeding has now been solved 
and we presently have a well established colony of seven generations with suffi- 
cient numbers of animals for experimental use. From all observations, the Euro- 
pean hamster has adapted quite well to laboratory life and, under standard 
conditions, the animals demonstrate no inclination toward hibernation. However, 
in the absence of hibernation, the lifespan of the hamsters may be shortened from 
the reported 8 years to 5 years. Nevertheless, this survival time still doubles the 
average span of the Syrian golden hamster. Of course, a longer survival time is a 
definite advantage for inhalation studies in carcinogenesis of the nasal and para- 
nasal spaces, larynx, trachea and lungs. 
Thus, our experimental animal has higher sensitivity to already known 
carcinogens and lives substantially longer than conventional laboratory rodents 
such as the mouse, rat and Syrian golden hamster. In addition, the European 
hamster, similar to the Syrian golden hamster, is free of infectious diseases of the 
respiratory tract. It is clear, then, that the European hamster is the animal of 
choice for studies in chemical carcinogenesis. Accordingly, yve are engaged in 
enlarging our breeding colony and maintain the hope that other scientists will 
also use this species in their investigations. We are making everv effort to place 
enough breeding pairs at the disposal of others. 
For studies in experimental carcinogenesis, it became apparent that a 
knowledge of the anatomy of C. cncetus would be especially useful. It must be 
possible to detail exactly the location of lesions to establish higher confirmation 
of species sensitivity to carcinogenic challenge. For this reason the present work 
on the anatomy of the European hamster has been compiled. The reader should 
bear in mind that we have placed special importance upon the respiratory tract. 
Moreover, the conventional systemic treatment of anatomical structure has been 
replaced in favor of topical regionalization, compatible with the purpose of a 
work designed especially for the non-anatomist in experimental pathology. 
Accordingly, attention is given to traditional mammalian body regions, including 
sections of all relevant organ systems and their relations, rather than exhaustive 
and exclusive treatment of single systems independent of region. 
[Figures 0-1 and 0-2 are located on pp. 4 and 5, respectively. I 
