Haseman made his long journey with a very slender equipment, his extraordinarily successful field-work being due to his bodily health and vigor and his resourcefulness, self-reliance, and resolution.
There is, however, one serious criticism to be made on Haseman: the extreme obscurity of his style--an obscurity mixed with occasional bits of scientific pedantry, which makes it difficult to tell whether or not on some points his thought is obscure also.
There is no better example of the kind of zoologist who does first- class field-work in the wilderness than John D. Haseman, who spent from 1907 to 1910 in painstaking and thorough scientific investigation over a large extent of South American territory hitherto only partially known or quite unexplored.
Haseman's primary object was to study the characteristics and distribution of South American fishes, but as a matter of fact he studied at first hand many other more or less kindred subjects, as may be seen in his remarks on the Indians and in his excellent pamphlet on "Some Factors of Geographical Distribution in South America."
Mr. Haseman drags it in continually when its use is either pointless and redundant or else serves purely to darken wisdom. He speaks of the "Antillean complex" when he means the Antilles, of the "organic complex" instead of the characteristic or bodily characteristics of an animal or species, and of the "environmental complex" when he means nothing whatever but the environment.