186 Trypanosoma lewisi 
elsewhere (1914). These bodies, first described by Carini, are round 
or oval, rarely pear-shaped, and stain a pale blue colour with Giemsa. 
They vary in size but on an average measure 5 to 6 p in diameter. 
Each cyst contains eight small bodies which stain a deep blue colour 
and have a round or oval nucleus. In addition to the enclosed mero- 
zoites a number of similar bodies were seen free or enclosed in a bluish 
matrix. 
Carini regarded them as forms of schizogony of T. lewisi and stated 
that they were derived from trypanosomes which had become encysted. 
Delanoe (1912) concludes that they represent a new parasite of rats, 
which has nothing to do with T. lewisi and terms them Pneumocystis 
carinii, and regards them as belonging to the Coccidia. 
Figs. 20 and 21 represent these bodies which were found in the lung 
smear of an old rat killed 23. vm. 1912, in which no T. lewisi were 
found, whilst those shown in Fig. 22 are from the lung smear of Rat E, 
1914, which showed numerous ordinary trypanosomes. They are 
depicted here merely as a contrast to the group of four trypanosomes, 
Figs. 5 and 13, and not as evidence of their being a stage in the develop¬ 
ment of T. lewisi. 
Multiplication Cysts of T. lewisi. In a him made from the heart 
blood of the small Rat A, 10. xn. 1913, I found a very interesting and 
to me entirely new type of body which is represented by Fig. 15. This 
rat was a small not fully developed specimen in which fairly numerous 
ordinary adult trypanosomes were present in the peripheral and heart 
blood, and in which coiled up trypanosomes and the four minute 
trypanosomes were found in the blood of the lung. 
This structure was nearly round and measured 14 by 15 p in 
diameter. The protoplasm stained a faintly blue colour with Giemsa 
and was of a somewhat alveolar nature. Contained within this sphere 
were a number of small round bodies stained a chromatin red colour 
which measured about 1 p in diameter, whilst nearly applied to each 
was another smaller granule staining a little deeper in colour, sometimes 
round, sometimes rod-shaped. 
A careful search of this preparation revealed a second similar body, 
Fig. 16 (x 2000), which stained in the same way, and contained the same 
red bodies, but different in being very vacuolated. This measured 
about 18 p in diameter. 
Although I searched films made from the blood of the heart and lungs 
of several other rats I only once again met with a similar structure 
and that (see Fig. 17) was found in the lung smear of a rat of average 
